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best reverse osmosis system

Best Reverse Osmosis Water Filters 2023: 12 Top Picks & Buying Guide

Trying to find the best reverse osmosis system for your home?

You've come to the right place. 

In this in-depth buying guide, we will help you choose the best reverse osmosis (RO) system for your home.

We explain exactly how an RO system works, why you might need one in your home, and what to look for when shopping for one.

We also recommend the best reverse osmosis filters available online. These include large systems for large homes, small countertop units that you can even carry around and everything in between.

Best Reverse Osmosis Filters 2023

HydroPerfection Ro System
  • Home Master TMHP HydroPerfection

  • Dimensions: 12 x 16 x 20 inches
  • Weight : 18.75lbs
  • With pH Filter: Yes
  • Daily Water Capacity (GPD): 75
  • Number of Stages: 6
  • Reserve Tank Water Capacity: 3.2 gallons

Reverse Osmosis System
  • iSpring RCC7AK

  • Dimensions : 14.5 x 5.2 x 18.5 inches
  • Weight : 20lbs
  • With pH Filter : Yes
  • Daily Water Capacity (GPD) : 75
  • Number of Stages: 6
  • Reserve Tank Water Capacity: 2.5 gallons

best reverse osmosis system
  • APEC RO-90 Supreme

  • Dimensions: 16 x 5.2 x 17.5 inches
  • Weight: 25lbs
  • With pH Filter : No
  • Daily Water Capacity (GPD): 90
  • Number of Stages : 5
  • Reserve Tank Water Capacity : 3.2 gallons

iSpring RCC7 5-Stage
  • iSpring RCC7 5-Stage

  • Dimensions: 14.5 x 5.2 x 17.5 inches
  • Weight : 25lbs
  • With pH Filter: No
  • Daily Water Capacity (GPD): 75
  • Number of Stages: 5
  • Reserve Tank Water Capacity : 3.2 gallons

best reverse osmosis system
  • Express Water RO5DX 5 Stage

  • Dimensions : 16.2 x 18.8 x 18.1 inches
  • Weight: 30.8lbs
  • With pH Filter : No
  • Daily Water Capacity (GPD): 50
  • Number of Stages : 5
  • Reserve Tank Water Capacity : 3.2 gallons

Home Master TMAFC RO System
  • Home Master TMAFC-ERP Artesian

  • Dimensions : 12 x 16 x 20 inches
  • Weight : 14.5lbs
  • With pH Filter : Yes
  • Daily Water Capacity (GPD) : 75
  • Number of Stages : 7
  • Reserve Tank Water Capacity : 3.2 gallons

Reverse Osmosis System
  • iSpring RCC7AK-UV

  • Dimensions: 14.5 x 5.2 x 19.5 inches
  • Weight : 31lbs
  • With pH Filter: Yes
  • Daily Water Capacity (GPD): 75
  • Number of Stages: 7
  • Reserve Tank Water Capacity: 2.5 gallons

best reverse osmosis system
  • APEC ROES-PH75 Alkaline Mineral pH+

  • Dimensions : 16 x 5.2 x 17.5 inches
  • Weight : 25lbs
  • With pH Filter : Yes
  • Daily Water Capacity (GPD) : 75
  • Number of Stages: 6
  • Reserve Tank Water Capacity: 3.2 gallons

best reverse osmosis system
  • Express Water ROALK10DCG 10-Stage

  • Dimensions: 18.2 x 18 x 16 inches
  • Weight: 27lbs
  • With pH Filter : Yes
  • Daily Water Capacity (GPD): 100
  • Number of Stages : 10
  • Reserve Tank Water Capacity : 3.2 gallons

best reverse osmosis system
  • APEC RO-CTOP-C Portable Countertop

  • Dimensions: 14 x 6 x 6.5 inches
  • Weight : 7lbs
  • With pH Filter: No
  • Daily Water Capacity (GPD) : 90
  • Number of Stages: 4
  • Reserve Tank Water Capacity : N/A

APEC ROES-50 RO System
  • APEC ROES-50

  • Best 5-Stage RO System
  • Dimensions : 5.2 x 16 x 17.5 inches
  • Weight: 26lbs
  • With pH Filter : No
  • Daily Water Capacity (GPD) : 50
  • Number of Stages : 5
  • Reserve Tank Water Capacity : 3.2 gallons

Waterdrop RO Reverse Osmosis Water Filtration System, 600 GPD
  • Waterdrop WD-G2P600-W

  • Best tankless RO system
  • Dimensions : 17.33 x 5.91 x 13.98 inches
  • Weight: 26.7lbs
  • With pH Filter : No
  • Daily Water Capacity (GPD) : 600
  • Number of Stages : 6
  • Reserve Tank Water Capacity : Tankless

What is Reverse Osmosis?

best reverse osmosis system

Reverse osmosis is the most reliable method of water filtration and purification.

Unlike other water filters like activated carbon that produce filtered water(meaning it still contains certain impurities), a reverse osmosis system provides purified water.

Purified water is free of almost all kinds of impurities from large ones like silt to microscopic ones such as bacteria –anything larger than 0.001 microns.

Because of its ability to remove a wide range of impurities from water, a reverse osmosis system offers the best protection for your family compared to other types of water filters.

Why Purchase an RO System?

best reverse osmosis system

Experts often recommend RO filters for water that might be biologically unsafe, meaning it contains waterborne pathogens like Cryptosporidium and Giardia.

That’s because no other filter is as effective as an RO system at removing microbes from water.

But even if you receive treated city water that is likely free of dangerous bacteria, you can still benefit from an RO water filter.

It can remove many other impurities that most other filters leave behind including dissolved salts, heavy metals and chemicals.

An RO water filter works as well filtering city water as it does well/artesian water.

However, you may need to pre-treat well water first to remove iron, hardness minerals and other impurities that can affect the RO filter and reduce its performance and lifespan. 

Best RO System Reviews

1. Our Top Overall Pick: Home Master TMAFC-ERP Artesian RO System

home master tmafc-erp

This Home Master RO system is one of the highest rated RO water filters on Amazon, with an almost perfect 5-star rating.

It’s also our top pick for the best reverse water filter for several reasons.

It’s better value for money compared to other expensive RO systems, it’s a breeze to install under the counter, it produces great tasting water, and it has a higher flow rate than almost any other RO system.

The only minor downside is that the installation takes a bit of time. If you are planning to install this yourself, block around 2-4 hours from your schedule.


  • Great value for money.
  • Double remineralization results in great tasting water.
  • Easy to install (though it takes time).
  • High flow rate – makes it easier to fill bottles and pitchers.
  • High performance 7-stage filtration process that removes almost all impurities.
  • Less water waste compared to other RO systems.


  • Installation takes time.

Key Features 

1. Multi-stage Filtration 

The Home Master under-sink RO system uses a combination of filters to remove up to 98% of sediment, chemicals, heavy metals, and dissolved salts.

These include a catalytic carbon filter that is much more effective than the normal activated carbon filter used in most RO systems.

The catalytic carbon in the Home Master can remove chlorine as well as chloramine.

The RO membrane removes heavy metals and harmful waterborne microorganisms.

2. Remineralization 

Reverse osmosis tends to be a bit too thorough when filtering water. It strips out minerals from water, including the good minerals.

This not only makes the water a bit less healthy for you, but it also makes it more acidic. The water has a certain unnatural taste.

The Home Master solves this by remineralizing the water twice. This reintroduces calcium and magnesium minerals, improving the taste of your drinking water and balancing out its pH.

3. 80% Less Wastage

Normal reverse osmosis filters waste about 4 gallons of water for every gallon purified. Over time, that’s a lot of water wasted.

The Home Master uses a non-electric permeated pump to reduce water waste by up to 80%.

Instead of flushing away 4 gallons for every gallon, it only wastes a single gallon for every gallon of purified water you use.

4. High Flow Rate

Another advantage of the permeate pump is an increase in water production.

Most reverse osmosis water filters produce purified water in a trickle. The Home Master has double the flow rate, making it so much easier to fill your water bottle.

5. Durable and Low-Maintenance Modular Design

One area where the Home Master stands out from other RO filters is the filter design.

With most systems, the filter cartridges are put inside filter housings.

When it’s time to replace the filters, you just have to remove the cartridge and put in a new one.

But the filter housing themselves are not replaced for several years. Eventually,  the stress and scale buildup in the houses causes them to break and leak. In some cases, the houses can flood your home.

Home Master uses a modular design where both the housing and the filter are one.

When you replace the filters annually, you replace even the housings. This keeps the system functioning at its best and ensures durability.

reverse osmosis systems

Issues & Limitations

1. Installation Takes Time

The only issue with the Home Master Artesian System is that installation takes time.

But this is normal for under counter water treatment systems.

What makes Home Master’s installation take even longer is that you need to drill a hole in the sink for the dedicated faucet and another hole in the drain line for draining away the wastewater.

You can hire a plumber if you want, but you should be able to set up the filter yourself in an afternoon.

Avoid this one if: You are looking for a compact counter top RO system for your kitchen, boat, or RV.

The Bottom Line

The Home Master Artesian RO filters are best for: Families and individuals looking for a high performance but affordable under counter RO system that is easy to install, easy to maintain, and lasts long.

2. Best RO System For Removing Biologicals: Home Master TMHP HydroPerfection

reverse osmosis filter

The Home Master Hydro-Perfection RO system integrates a UV filter to sterilize your water, killing most waterborne microbes.

If you want complete peace of mind that your family is drinking the safest possible water, then this is the best RO system to buy.

It doesn’t matter whether you use city or well water, the Home Master HydroPerfection will keep your drinking water safe and your cleaning water free from minerals, toxins and other contaminants.

Like the HomeMaster Artesian system, this one installs under the counter.

Installation is easy, but can take some time.


  • Integrated UV filter provides extra protection.
  • Easy to install under the counter.
  • Includes a remineralization stage to restore the taste and pH of water.
  • High flow rate makes it easy to fill water bottles and pitchers.
  • Iron pre-filter makes it ideal for both well and city water.
  • Modular filter design increases durability.


  • Installation takes time.
  • Pricey.

Key Features 

1. Five Filters Including UV

The Home Master HydroPerfection uses multiple stages to remove over 98% of impurities in water including 99.99% of microorganisms.

Sediment filter: Removes fine sediment and silt suspended in water.

KDF85 iron filter: Home Master HydroPerfection is one of the few RO systems you can use with well water without having to pre-treat it. It comes with an iron pre-filter (for iron levels up to 1 PPM) to protect the carbon filter and RO membrane. 

Catalytic carbon filter: Removes chlorine, and chloramine. Also filters out heavy metals, dissolved minerals and chemicals.

RO membrane: Removes heavy metals, dissolved salts, chemicals, cysts, bacteria, and viruses.

UV filter: Kills or neutralizes microbes by damaging their DNA. 

Activated carbon post-filter: Provides a final polish to the water.

2. Full Contact Remineralization 

To make sure the water is not too acidic and unnatural tasting, the Home Master HydroPerfection system includes a remineralization stage.

Calcium and magnesium are added to the water, which balances the pH and makes your water tastier.

3. Less Water Wastage 

The RO filter includes a non-electric permeate pump that reduces the amount of water wasted by up to 80%.

Most reverse osmosis filters have wastewater to purified water ratio of 4:1 gallon. The Hydro Perfection wastes only 1 gallon for every gallon of purified water consumed (1:1 ratio).

4. Higher Flow Rate

The permeate pump also increases the production of purified water, ensuring you won’t have to endure a trickle like with most RO systems.

The filter further increases the flow rate by using larger fittings.

5. Modular Filter Design 

HydroPerfection RO Water Filter

The HydroPerfection features Home Master’s signature modular design that combines the filters and filter housings into one.

After one year, you’ll replace both the filters and the filter cartridges.

This greatly improves performance and durability compared to traditional RO systems that use filter cartridges.

Issues and Limitations 

Installation Takes Time 

The main issue with the Home Master Hydro Perfection is that the installation process is long.

Installing the filter under your counter is easy – you don’t have to call a pro. But expect to spend at least 2-3 hours connecting it to your cold water line and drilling a hole on your sink for the new faucet.


The addition of a UV sterilizer and an iron pre-filter adds to the price tag of the Home Master HydroPerfection, making it one of the more expensive under-sink RO systems in the market. 

Avoid this one if: You are looking for a compact and easy-to-install counter-top RO filter. Also not suitable if you are shopping for a budget RO system.

Our Bottom Line 

The Home Master Hydro-perfection RO system is perfect for anyone looking for a premium RO system that provides extra protection against waterborne bacteria and viruses. 

It's also an excellent choice for homes that use well water. 

3. Best Priced RO System: iSpring RCC7AK Reverse Osmosis System

ro filter system

RO systems tend to be more expensive than other types of filters. Some of the most powerful ones cost well over $500.

If you are not ready to spend that much money on an RO filter, we recommend the budget iSpring RCC7AK.

The iSpring RCC7AK is one of the least expensive RO systems sold today, but it doesn’t sacrifice the most important features. It comes with a 5-stage filtration process plus a remineralization stage to restore your water’s natural taste.

Installation under the counter is easy, but it takes some time.


  • Great value – affordable with comparable performance to more expensive filters.
  • Includes a remineralization stage to reduce water acidity and enhance taste.
  • Clear sediment filter lets you know when it’s time to replace it.
  • Easy to install.


  • Installation takes time – at least 2 hours.
  • Relatively high water wastage.
  • Relatively low water pressure.
  • Not ideal for well water.

Key Features 

1. 5-Stage Filtration 

Here are the five filters water passes through:

  1. Sediment filter: Removes sediment and silt. This filter is clear so you can see the impurities removed from your water and know when it’s time to get a new filter.
  2. Activated carbon filter with KDF: Removes chlorine, chloramine, chemicals, and heavy metals.
  3. Carbon block filter: Further removes chlorine, organic chemicals, fine sediment, and heavy metals.
  4. 0.0001-micron RO membrane: The ultra-fine membrane removes almost all the contaminants left in the water, including viruses and bacteria.
  5. Activated carbon post-filter: Provides a final polish to the water before it goes to the remineralization stage.

2. Remineralization 

This is where the minerals stripped from water are put back, specifically magnesium and calcium (don’t worry, the amount of minerals added won’t make your water hard).

This raises the pH of water, making it healthier for drinking, cooking, taking medicine, and making baby food.

It also gives the water a more natural taste.

3. Easy Undercounter Installation

You can definitely install this filter yourself. There’s no need to hire a pro even if you’ve never done any DIY plumbing.

But be ready to spend at least two hours hooking up the filter to your cold water line and installing the new faucet.

I’d say it’s an afternoon's worth of work.

But at least the filter comes with everything you need including push to connect fittings and color-coded tubing.

ro filter system

Issues and Limitations 

1. No Permeate Pump

This RO filter doesn’t come with a permeate pump that would significantly reduce water waste and increase water pressure.

It wastes more water than most RO filters (around 4 gallons for every gallon) and has a lower flow rate.

It can be a bit frustrating to fill a large bottle or pitcher.

But for the price, this is an acceptable sacrifice. And you can always buy a permeate or electric pump separately and attach it to the system.

Avoid this one if: You want an RO filter with a high flow rate. Also not ideal for homes that use well water.

Our Bottom Line 

The iSpring RCC7AK is best for: Anyone looking for a budget but good quality RO filter.

4. Largest Capacity RO System: APEC RO-90 Supreme Reverse Osmosis System

reverse osmosis water filtration system

The affordable APEC RO-90 has twice the filter capacity of other RO filters in the same price range.

Most budget RO systems use 6-month filters, meaning you have to buy new filters twice a year. But the RO-90’s filters last 12 months, similar to the filters in more expensive RO systems.

The added capacity makes maintenance easier and cheaper.

There are 5 filters in all, including double carbon blocks that remove unpleasant tastes and smells from your tap water.

Unfortunately, the RO-90 lacks a remineralization stage. Your drinking water won’t have than nice bottled water taste that other RO systems produce by adding minerals.


  • Affordable.
  • High performance 5-stage filtration.
  • High capacity filters that last for longer.
  • Easy to install.
  • High daily output - great for big families. 


  • Poor documentation.
  • Low flow rate.

Key Features 

1. 5-stage Filtration 

Sediment filter: removes suspended particulates including dust, silt, and rust. This protects the RO membrane and the carbon filters from clogging up too soon.

Two carbon blocks: To make sure your water tastes fresh, the system uses two large carbon blocks to remove chlorine and other chemicals that affect the taste and smell of water. Unfortunately, these carbon blocks do not remove chlorine.

RO Membrane: Removes over 99% of impurities, including chemicals, heavy metals, dissolved solids, viruses, and bacteria.

Carbon post-filter: Removes any remaining smells and tastes.

2. High Capacity Filters

The filter replacement period is a convenient 12 months. This is a double the capacity of RO filters in the same price range.

This not only makes maintenance easier, but you also spend less money. 

3. High Daily Output

With an output of 90 gallons per day, the iSpring RO-90 is a great choice for large households that consume lots of purified water. 

It beats the standard 50-75 GPD output of most other RO systems. 

4. Easy Undercounter Installation 

The system is easy to install undercounter though it takes a bit of time. I recommend setting aside at least 2-3 hours for the installation.

All parts and fittings are provided including a lead-free chrome faucet.

The only issue is that the manual is written poorly. But there are several helpful installation videos online you can follow.

Issues and Limitations 

1. Vague Installation Instructions 

The main complaint from customers is the manual. It could have been more details and clear.

But even with the poorly written manual, installing the filter is still fairly easy. If you get stuck, there are some installation videos online. You can also contact their very helpful customer support team.

2. Limited Flow Rate 

The other issue is the low flow rate. This model doesn’t have a permeate pump so, water comes out at just a little bit more than a trickle. It’s tedious to fill up a large bottle.

If you want higher water pressure, you have to buy a separate permeate pump and install it.

3. No Remineralization

Another limitation is the lack of a remineralization stage, which is available in most other RO systems. Because the stripped minerals are not added back, the water tastes slightly unnatural.

But most people don’t notice the difference. If you don’t care about your drinking water tasting exactly like bottled water, then this is not a problem.

Avoid this one if: You want a reverse osmosis filter with a high flow rate or mineralization.

Our Bottom Line

The APEC RO-90 is best for: Anyone with a large family looking for an affordable RO water system with a long lasting filter.

5. Best Value RO System: iSpring RCC7 5-Stage Reverse Osmosis System

ispring rcc7 wqa gold seal certified 5-stage reverse osmosis drinking water filter system

The iSpring RCC7 RO system provides the best value for your money, in our opinion.

It’s less expensive than most other water filters in this guide but it provides comparable features and performance.

The RCC7's 5-stage filter system capable of removing up to 99% of over a thousand contaminants ranging from chlorine to cysts and bacteria.

Installation under the counter takes a couple of hours. All the parts you need are included.

Being a budget RO filter, there are some sacrifices. The RCC7 has relatively low water flow, waste water is on the higher end and there’s no remineralization stage.

But when it comes to what matters most, giving your family safe purified water, the RCC7 matches other systems for way less money.


  • Excellent value for money –cheaper but with similar performance to pricier RO filters.
  • Easy DIY installation.
  • High performance 5-stage filtration – removes over 1000 contaminants.
  • Easy maintenance.


  • Low water flow.
  • Higher water wastage.
  • No remineralization stage.

Key Features 

1. 5-stage Filtration

Water passes through 5 stages that systematically remove specific contaminants at each stage, as follows:

  • Pre-filter that removes sediment, rust, sand and other particulates suspended in water. This filter has a see-through housing, which allows you to monitor filter life.
  • Granulated activated carbon (GAC) filter removes cloudiness, chlorine taste and any unpleasant smells.
  • CTO filter removes chloramine, organic chemicals and VOCs.
  • A 0.0001-micron RO membrane removes any remaining contaminants including heavy metals, chemicals, cysts, bacteria and viruses.
  • A carbon post-filter removes residual tastes and odors to completely freshen up your drinking water.

2. Easy Undercounter Installation

Installation takes about 2 to 3 hours depending on your experience in DIY plumbing.

But you don’t have to call a pro. All the parts and fittings you need are included along with the RO filter. All you need are tools to connect the system to your cold water line and drill a hole for the new faucet.

The faucet is an upgraded European-design made from brushed nickel. It’s not the most luxurious faucet you can get but it looks pretty good.

iSpring RCC7AK-UV Under Sink RO

3. Low Maintenance

The RCC7 system doesn’t require much in terms of maintenance. Your only job is to monitor filter life and replace the filters when necessary.

Apart from the RO membrane, which has a 2-3 year lifespan, the other filters have a lifespan of 6-12 months.

Because the system has no filter replacement reminder, I recommend using the clear first stage housing to determine when it’s time to get new filters.

When the first filter fills up with sediment, replace it along with the other filters (except the RO membrane).

Issues and Limitations 

High Wastage and Low Flow

The RCC7 doesn’t have a permeate pump, which is used in more expensive filters to reduce water wastage and increase flow rate.

As a result, the water comes out of the faucet in a weak stream that takes a while to fill up a large water bottle or pitcher.

The system also wastes more water than pricier RO filters.

The wastewater to purified water ratio is 3:1, meaning 3 gallons of ‘dirty’ water are drained for every gallon of purified water you use.

Avoid this one if: You are looking for an RO system with low water wastage and high water flow rate. Get a system with a permeate pump instead.

The Bottom Line 

The iSpring RCC7 reverse osmosis system is best for: Anyone looking for a budget but high performance reverse osmosis system.

6. Best Budget Buy: Express Water RO5DX 5 Stage Reverse Osmosis System

reverse osmosis water filter reviews

The Express Water RO5DX is the least expensive RO filter we recommend.

That doesn’t mean it has the lowest performance, however.

Performance-wise, the RO5DX is as good as several more expensive systems. It uses a 5-stage filtration process that removes most of the impurities from water.

The final water quality is as good as bottled water.

The RO5DX does lack two important features: a remineralization stage and a permeate pump. At 50 GPD, its daily output is also fairly low, making it less than ideal for large households. 


  • One of the cheapest RO water filters.
  • Easy DIY installation.
  • High performance 5-stage filtration.
  • Fast flow faucet.


  • Filters are a bit tedious to replace.
  • Not ideal for large families.

Key Features 

1. 5-stage Filtration

The system is divided into a pre-filter stage, the main RO membrane filtration stage and post-filtration. Altogether, these stages consist of media as follows:

  • Sediment filter: Removes small rocks, sediment, silt, dust, sand and rust. This not only cleans up your water, it also prevents the sediment from damaging the other filters and shortening their lifespan.
  • GAC / Carbon Block filters: These two filters remove chlorine, chloramine, organic chemicals and any other impurities that give water an unpleasant taste/smell. They also protect the RO membrane from damage by chemicals like chlorine.
  • RO membrane: Removes the most stubborn impurities like fluoride, arsenic, mercury, lead and total dissolved solids.
  • Carbon post-filter: Polishes up the water by removing any residual odors and tastes.

2. Easy DIY Installation 

The filter comes halfway assembled, making installation much easier.

Everything you need is in the package, including and adaptor for 3/8" and 1/2" connections.

All you need is an adjustable wrench, a power drill and ¼” and ½” drill bits.

The system uses quick connect tubings that are really easy to work with. All the tubes are color-coded depending on where they are supposed to go.

Overall, installation takes a couple of hours.

3. Leak Stop Valve

The system includes an automatic leak detection mechanism that shuts off water supply to prevent flooding.

It consists of a simple fabric disc that stays in contact with the floor under your sink. If the fabric absorbs water, a valve closes immediately.

Issues and Limitation 

1. Average Daily Output

If you use a lot of purified water in your home, the 50 GPD output of the RO5DX may not be adequate. 

Consider getting a 75 GPD RO system or the 90 GPD iSpring RO-90. 

If that's still not enough, see our review below of the 600 GPD tankless Waterdrop RO system. 

2. Tedious Filter Replacement

The other issue is about filter replacement. The filters are actually cloth cartridges inside cylinder housings.

So instead of replacing the entire part, you have to open the filter housing, remove the wet and dirty filter and wash the housing before putting in a new filter.

Filter replacement takes longer and is messier than in systems that use all-in-one filters.

Avoid this one if: You use more than 50 gallons a day of purified water for drinking, cooking, pets and other uses. 

The Bottom Line

The Express Water RO5DX is best for: Families and individuals looking for a cheap but good quality reverse osmosis water filter.

7. Best-Featured RO System: iSpring RCC7AK-UV Reverse Osmosis System

reverse osmosis water filter reviews

The RCC7AK-UV reverse osmosis filter is a more advanced version of the iSpring RCC7 and RCC7AK systems we have already reviewed.

It adds two more filter stages to the 5 basic stages of its sibling filter:

One of them is a remineralization stage to enhance the taste of water and make it healthier.

The other is a UV filter to provide added protection against microbes.

As expected, the RVV7AK-UV is more expensive than the RCC7 and RCC7AK. But it’s still surprisingly affordable considering the extra features.


  • Includes a remineralization stage that improves the taste of water.
  • High performance 7-stage filtration that includes a UV filter.
  • Easy DIY installation.
  • Includes a water detector to prevent leaks and flooding.


  • Installation takes time.
  • Slightly more expensive than other basic models.

Key Features 

1. 7-Stage Filtration with Remineralization and UV 

The first five stages are the same ones in the RCC7 and RCC7AK.

There’s a sediment pre-filter to remove suspended particulates like sand and dust, two carbon filters (GAC and CTO) to remove chemicals, chlorine and chloramines and an RO membrane that removes heavy metals, TDS, bacteria and viruses.

There’s also a post carbon filter to polish up the water.

But before the water goes to the storage tank, it passes through a couple more stages.

pH/remineralization filter: Minerals stripped from the water are added back to improve taste and increase pH. This makes the water healthier and tastier.

UV filter: Intense UV light kills off any remaining microbes to ensure your water is completely safe to drink.

iSpring RCC7AK-UV

2. Easy Undercounter Installation

The RCC7AK-UV installs under your counter in 2-3 hours. You can hire a pro if you don’t have the time to install it but it’s not necessary.

The system is easy to install. All the fittings, connectors and a faucet are included. All you need is a wrench to open and tighten connectors and a drill to make a hole on the sink for the faucet.

If your sink already has an existing hole, you can use that instead.

3. Water Leak Detector

In case there is a leak somewhere in the system, a water detector will immediately sound an alarm to prevent flooding.

Issues and Limitations 

1. No Permeate Pump

Despite costing more, the RCC7AK-UV doesn’t have a permeate pump. So don’t expect a powerful water stream that fills bottles in seconds.

The system also wastes more water than filters with a permeate pump. The waste to purified water ratio is 3:1.

Avoid this one if: You are shopping for a cheap (under $200) under-sink RO system.

The Bottom Line 

The RCC7AK-UV RO water filter is best for: Families that want an RO filter with extra protection against biological contaminants (bacteria, cysts and viruses). Also ideal for those who want an RO filter with a remineralization stage to give their water a bottled water taste.

8. Best RO System With Re-Mineralization: APEC ROES-PH75 Alkaline Mineral pH+ RO System

ro system

If you want your purified water to taste like bottled water, look for a reverse osmosis system with a remineralization stage that adds stripped minerals back to the water.

The APEC ROES-PH75 is one of the most affordable RO systems that produces bottled water quality mineralized water. The resulting water is healthier and tastes better than non-mineral purified water from other RO systems.

The water passes through four filtration stages before going through the remineralization stage where calcium carbonate is added.


  • Great tasting water – it tastes just as good as premium bottled water.
  • Balanced pH water, which is healthier.
  • High performance filtration – 5 filters remove almost all impurities in your water.
  • Easy to install under the counter.


  • High water wastage ratio.
  • Some of the installation instructions are confusing.
  • No water leak detector.

Key Features 

1. Five High Capacity Filters

Not counting the pH filter/remineralization stage, the APEC ROES-PH75 cleans up water using five filters, as follows:

  • Polypropylene sediment filter: Removes sediment, rust, silt and other particulates suspended in water.
  • Dual carbon blocks: These remove chlorine, chloramine, VOCs and organic chemicals. Essentially, they improve the color, taste and odor of water by filtering out various chemicals.
  • 0.0001 RO Membrane: Removes heavy metals, total dissolved solids (TDS), bacteria, cysts and viruses.
  • Refining carbon filter: Water passes through this filter for a final polishing just before it gets out of the faucet. This removes any remaining odors and tastes.

All of the above are high capacity filters that should last up to 12 months on city water. 

The RO membrane and the post filter last even longer – around 2-3 years.

However, if you receive well water in your home, the manufacturer recommends replacing the first 3 filters sooner than 12 months. A 6-month schedule is ideal to keep the system at its best.

2. Remineralization Stage

During this stage, calcium carbonate is added to the water which achieves two things:

  • It enhances the taste of water. Mineral water has a sweeter more natural taste.
  • It increases water pH. RO purified water tends to be acidic, which is not healthy (it causes cell-damaging oxidation). Adding minerals increases the pH to neutral or slightly alkaline. It’s not as healthy as strong alkaline water but it’s better than acidic water.

3. Easy Installation

The system is relatively easy to install.

All the fittings and parts are provided including filter wrenches, a drain saddle and a brushed nickel faucet.

You just need to have the right tools with you including a drill to make a hole for the faucet.

Installation instructions are generally clear except when it comes to installing the pH filter. Most people found that part a bit difficult because of poor labeling and instructions on the manual.

To avoid any problems, I recommend watching an installation video to get an idea of how the 6 stages are put together.

Issues and Limitations 

1. Wastes a Lot of Water

The APEC ROES-PH75 has a wastewater to purified water ratio of 3:1. That’s fairly high compared to systems that can achieve a 2:1 or 1:1 ratio.

The high water wastage ratio is primarily because of the lack of a permeate pump, which also reduces water flow rate out of the faucet.

2. No Leak Detector

Something else lacking is a water leak detector, a feature you’ll find even in cheaper RO systems.

It’s important that you regularly check for leaks yourself and fix them before they cause flooding.

Avoid this one if: You are looking for an RO system with a low waste to filtered water ratio.

The Bottom Line 

The APEC ROES-PH75 RO filter is best for: Anyone looking for an affordable reverse osmosis filter that produces great tasting mineral water.

9. Best RO System For Alkaline Water: Express Water ROALK10DCG 10-Stage RO System

ro filter system

RO purified water is slightly acidic. That’s because the RO membrane strips out mineral ions.

Some reverse osmosis systems have a remineralization stage that adds back some of these minerals, usually calcium and magnesium.

But this doesn’t fully counter the acidity issue. The best it does is increase the pH to neutral, the same level as your normal tap water.

The Express Water ROALK10DCG system not only rids your water of impurities, it also produces alkaline water, which is full of healthy antioxidants


  • High performance 10-stage filtration.
  • 5-stage alkalization filter produces healthy alkaline water.
  • Great tasting water.
  • Includes a leak stop valve to prevent flooding.
  • High daily capacity – up to 100 gallons a day.
  • Easy undercounter installation.


  • Installation takes time. Set aside at least 2 hours.

Key Features 

1. 5 Filter Stages

While the manufacturer calls this a 10-stage RO water filter, there are only five actual filters. The other five stages are all for remineralization.

  • Sediment filter: Removes dust, silt, sand and sediment.
  • Carbon block and granular activated carbon: These two filters target chemical compounds that affect the taste and smell of water including chlorine, chloramine, VOCs and organic chemicals.
  • RO Membrane: Removes stubborn contaminants like lead, fluoride, arsenic, mercury and other heavy metals. Also filters out microbes including bacteria and viruses.
  • Post carbon filter: Removes any remaining odors and cloudiness from the water right before it comes out of the faucet.

2. Remineralization Filter 

The pH/remineralization filter is located between the RO membrane and the post carbon filter.

In this stage, several minerals are added to the water, raising alkalinity and enhancing its taste.

The final water is full of healthy minerals and has a pH of about 8-8.5.

High pH water, or simply alkaline water, contains more antioxidants than neutral or acidic water.

Though research is still ongoing, some studies indicate that alkaline water can help with reflux, inflammation and skin problems.

under sink reverse osmosis water filter reviews

3. Simple DIY Installation 

You don’t need to hire a pro to install the Express Water filter. It’s designed for DIY installation with all the parts and fittings provides and accompanied by clear instructions and pictures.

If you encounter any issue, the company’s customer support team is very helpful.

But I have to warn you – setting up the filter can consume an afternoon.

Most people finish installation in 2 hours. But to be safe, set aside at least three hours especially if this is your first DIY plumbing project.

Issues and Limitations 

1.  Installation Time

Easy doesn’t mean fast.

While you won’t have much trouble installing the Express Water RO filter, expect to spend at least 2-3 hours setting it up.

The part that takes up most time is drilling a hole for the new faucet. You have to be extra careful to do it right. If you get it wrong, there’s no going back.

If your sink already has a hole for soap, you luckily won’t have to make another one.

Avoid this one if: You don’t care much for extra minerals in your water – you just want a basic RO filter system.

The Bottom Line 

The Express Water ROALK10DCG system is best for: Families looking for an RO filter that produces healthy alkaline mineral water.

10. Best Portable RO System: APEC RO-CTOP-C Portable Countertop RO System

best reverse osmosis system

Most of the reverse osmosis systems you’ll come across are installed under your countertop.

This portable unit APEC is great for families who want a temporary RO system. It’s also perfect if you want to enjoy purified water on the go, in an RV or on a boat. 

It hooks up to most standard faucets in less than 10 minutes.


  • 10-minute setup on the countertop.
  • Compatible with most standard faucets – 3 adapters included for use with different types of faucets.
  • Portable – provides purified water on the go. Comes with case for easier portability.
  • High performance 4-stage filtration.


  • Low water flow rate.
  • Not ideal for a large family.

Key Features 

1. Easy Countertop Installation

A typical reverse osmosis water filter takes at least 2 hours to install.

In contrast,the APEC RO-CTOP-C is ready to use in 10 minutes.

That’s because you don’t have to disconnect any water lines or drill a hole in your sink.

The filter has a water diverter valve that attaches directly to your standard faucet.

The valve redirects tap water to the filter. Purified water comes out of an outlet line connected to the filter.

The diverter valve has another outlet attached to it for draining away the wastewater.

This filter is compatible with most standard faucets.

You just need to remove your faucet’s aerator, find an adapter that is compatible with your faucet (there are three adaptors included)and attach the diverter valve to the adaptor.

Attach the quick connect tubes as shown in the user manual and let the system flush for 10-15 minutes.

Note: The filter is not compatible with a sprayer, pull out or any special design faucets.

2. Four Filter Stages

Despite its compact size, the APEC RO-CTOP-C purifies water just as well as bigger systems, albeit at a much slower rate. It uses 4 filters to removes dozens of contaminants from water, as follows:

  1. Sediment filter: Removes suspended particulates like dust, sediment and sand. This filter is good for 6-8 months.
  2. Activated carbon filter: Removes chlorine and various organic chemicals. Replace the filter after 6-8 months.
  3. RO membrane: Removes heavy metals, total dissolved solids, cysts, viruses and bacteria. This filter lasts 2-3 years.
  4. Post carbon filter: Gives the water a final polish to remove any remaining odors and tastes.

This is the same number and arrangement of filters used in many full size undercounter systems.

The only difference is that the RO-CTOP-C purifies less water. Otherwise, you are guaranteed the same high quality.

3. It's Portable!

Most portable filters are non-RO systems. They are usually a combo of carbon and sediment filters that don’t come close to an RO filter’s capability.

With the RO-CTOP-C, you can finally enjoy safe purified water wherever you are.

Instead of carrying bottled water or risking unsafe tap water in a hotel, carry the filter with you and hook it up to the faucet.

The filter comes with a handy case you can safely carry it in.

Issues and Limitations 

1. Low Water Flow Rate 

For all its convenience, the RO-CTOP-C can be pretty tedious to use. The water comes out in a light stream that takes forever to fill a jug or bottle.

This makes the RO-CTOP-C less than ideal for large families.

Some customers found a good workaround to this issue. They fill large water bottles or pitchers with water. When they need drinking water, they pour it from the bottle rather than from the filter.

Avoid this one if: You are looking for a permanent high capacity reverse osmosis system for your family.

The Bottom Line 

The APEC RO-CTOP-C portable RO water filter is best for: Anyone looking for an easy-to-setup RO filter they can carry with them when traveling. Also perfect for use in an RV or a boat.

11. Best 5-Stage Reverse Osmosis System: APEC ROES-50 Reverse Osmosis System

APEC ROES-50 Top Tier RO System

If you are looking for a 5-stage reverse osmosis system that will reliably put out clean and great tasting water for years, the APEC ROES-50 is a solid choice.

Using a 5-level filtration system, the ROES-50 is capable of removing over a thousand impurities from the water from harmless ones like sediment to dangerous contaminants like mercury and bacteria.

The system is designed to produce up to 50 gallons of purified water per day, which is plenty even for a large family.


  • Good value for money – it’s surprisingly affordable for its level of performance.
  • Easy to install under the sink – everything you need is included.
  • Great tasting water – just as good as bottled water.
  • Long lasting parts.


  • Installation takes time.
  • No pH filter.

Key Features 

1. 5-Stage Filtration 

Here are the five filters water passes through:

  1. Sediment filter: Removes sediment, dust, rust and sand.
  2. Dual carbon blocks: These remove chemicals that affects the taste and smell of water such as chlorine, chloramine,hydrogen sulfide and VOCs. They also filter out harmful organic chemicals. The carbon blocks have a larger surface area than most filters to maximize performance.
  3. High rejection RO membrane: The RO filter removes heavy metals, TDS (total dissolved solids), cysts, bacteria and viruses.
  4. Refining coconut carbon filter: This post filter removes residual odors and tastes to ensure the water is spring fresh.
ro water system

2. Easy Undercounter Installation 

All the parts and fittings you need are included along with the filter.

APEC says the fittings are fitted with special O-rings and steel teeth to ensure there is no leaking. As a result, they don’t include a leak detector valve.

Having a leak detector would have provided complete peace of mind, but so far, most customers say the system doesn’t leak at all.

Installation takes about two hours to complete (I said it was easy not quick) with the most challenging part is drilling a hole in the sink for the faucet.

If you want, you can hire a pro to do the installation. But if you have an afternoon free, this is something you can do yourself. The instructions in the manual are detailed and easy to follow.

3. Long Lasting Filters

Most RO filters in this price range have 6-month carbon and sediment filters. The ROES-50 filters last a full year before you need to replace them.

This not only saves you time, but it also saves you money because you don’t have to buy replacement filters as often.

Note: If you use well water, you may have to replace the filters every 6 months. Use a TDS meter to monitor filter life.

Issues and Limitations 

1. Installation takes time 

Expect to spend at least 2 hours connecting the filter to your cold water line and installing the dedicated faucet.

2. No pH filter 

The ROES-50 produces slightly acidic water, which is not as beneficial as alkaline water.

Many undercounter RO filters include a pH filter in the system that adds minerals to the purified water to raise its pH and enhance the taste.

If you are looking for an RO system that produces mineral or alkaline water, this is not it.

Avoid if: You want an RO system that produces alkaline or mineralized water.

The Bottom Line 

The APEC ROES-50 RO water filter is best for: Families looking for an affordable reverse osmosis water filter that produces high quality purified water.

12. Best Tankless RO System: Waterdrop WD-G2P600-W Tankless RO System

best reverse osmosis systems

The Waterdrop tankless RO system has four advantages over traditional RO systems: it takes up less space under the sink, it has a high daily output of 600 GPD, it has a high flow rate from the faucet and it wastes less water. 

Tankless RO systems like Waterdrop eliminate the pressurized reserve tank that most RO systems use, and instead use an electric pump to provide purified water on demand. 


  • High daily output.
  • Fast flow rate from the faucet.
  • Space saving tankless design.
  • Less water wastage.
  • High performance 6-stage filtration. 


  • Expensive.
  • TDS creep.

Key Features

1. 6-Stage Filtration 

The Waterdrop WD-G2P600-W comes with two filter cartridges: a CF pre-filtration cartridge and an MRO cartridge. Within these two cartridges, the system packs 6 stages of filtration. 

The CF cartridge has two pre-filters: a sediment filter and an activated carbon filter. These remove sediment, rust, scale, chlorine, and various chemicals from the water. 

The MRO cartridge has four filters: an activated carbon filter, a sediment PP membrane, an RO membrane, and a PET pleated membrane. 

Together, these filters remove most of the remaining impurities from water including fine sediment, chemicals, heavy metals and microbes. 

2. High Output and Flow Rate

The 600 GPD daily output of the Waterdrop WD-G2P600-W dwarfs what traditional RO systems with a tank can produce. 

If you need lots of purified water, the Waterdrop tankless system is a great choice. 

The high output also means a high flow rate. Water from the Waterdrop faucet doesn't flow as fast as a normal kitchen faucet, but it’s not the slow trickle you get from other RO systems. You can fill a 200ml cup in just 8 seconds. 

3. Perfect for Small Under-sink Spaces

Traditional RO systems are bulky. The multiple water cartridges, tank and several water lines take up plenty of space under the sink. 

If you have limited under-sink space, the Waterdrop tankless system is a great choice. Without a tank and with all the filters integrated into a single unit, the system takes up less space. It measures 17.33 x 5.91 x 13.98 inches.

Keep in mind that you’ll need to have access to a power outlet. You may need to call an electrician to install one under the sink.

Issues and Limitations

1. You’ll Still Need to Drill a Hole

Because the Waterdrop WD-G2P600-W goes under the sink like other RO systems, you’ll still need to drill a hole on the countertop for the dedicated faucet. 

If you already have a hole for the soap dispenser, you can use that instead.     

2. Expensive

All the benefits of the Waterdrop WD-G2P600-W tankless RO system don't come cheap. It costs more than most traditional RO systems. 

But, in our opinion, the high price tag is worth it. 

3. TDS Creep

One issue many customers have reported is that when you first open the faucet, the initial water doesn't taste great and has high TDS. This is called TDS creep. 

It happens when high TDS water manages to pass through the RO membrane. It occurs when when you turn on the faucet, before the system’s pressure increases enough to properly filter water. 

The Waterdrop WD-G2P600-W takes a few seconds to ramp up pressure and produce purified water. 

There are two things you can do to go about TDS creep. One, let the water flow into the sink for the first few seconds after turning on the faucet. But it’s tedious to do this every time you want a drink. 

A better option is to store purified water in a pitcher in the refrigerator on the countertop. That way, you don’t need to use the RO faucet as frequently. 

Avoid this one if: You are shopping on a budget. A traditional RO system with a tank will cost you less.

The Bottom Line

The Waterdrop WD-G2P600-W is perfect for you if: you are looking for a high-output and low-wastage tankless RO system. It’s also a great choice for small under sink spaces. 

How Do Reverse Osmosis Filtration Systems Work?

best reverse osmosis system

To understand reverse osmosis;it is important to understand osmosis.

Osmosis is the movement of water from a solution with less salt to one that is more concentrated. The water moves through a semi-permeable membrane that only allows some molecules, mostly those of water, though.

Plants take in water from the soil through osmosis. It’s also how kidneys absorb water from the blood.

Reverse osmosis is, well, the reverse of osmosis. Water moves from a more concentrated solution to a less concentrated one.

But while osmosis occurs naturally, reverse osmosis requires pressure to force water to go against the natural osmotic pressure.

As the water is forced to move across the semipermeable membrane, it leaves behind 95-99% of dissolved salts as well as heavy metals and microbes.

What you get on the other end of the membrane is purified water that is almost completely free of impurities.

What remains on the concentrated side is the reject stream full of salts and other impurities. This ‘dirty’ water is drained away through some systems recycle it back into the system to extract more purified water.

This is the general reverse osmosis process. Home reverse osmosis systems work the same way but with a few additional steps involved. Here’s the journey your tap water takes through a typical undercounter RO system.
  • Water enters the RO system through an inlet tube. For filtration to occur, the water has to be coming in at a specific pressure.
  • The RO semi permeable membrane is not left to filter everything. It would damage the membrane and reduce its lifespan.
  • So reverse osmosis filtration systems have pre-filters, usually a sediment filter and one or two carbon filters. These remove sediment, rust, chlorine, chloramine and various chemicals.
  • The filtered water then passes through the RO membrane where virtually everything other than water is rejected.
  • Purified water comes out of the other side of the membrane and goes into a storage tank.
  • Some water is used to wash away the salts and impurities rejected by the membrane. This is the reject stream that is drained.
  • When you open the faucet, purified water comes out of the storage tank and passes through a final carbon filter before pouring out.

What Contaminants Do Reverse Osmosis Systems Remove?

  • Total dissolved solids such as calcium, magnesium, iron and other metal ions.
  • Heavy metals like lead and mercury.
  • Chemicals like arsenic, fluoride and nitrates.
  • Microorganisms including bacteria, cysts and viruses.

These are the impurities removed by the semi permeable membrane itself. Pre-filters remove additional contaminants including sediment, rust, chlorine and organic chemicals.

Buyer’s Guide

best reverse osmosis system

With so many different kinds of reverse osmosis systems and numerous brands in the market, it can be difficult to choose the best filter for your needs.

Use this checklist of important features to narrow down your options and find the system that works best for you.

Buyers Checklist

1. Gallons Per Day (GPD)

GPD is the amount of purified water an RO system can produce per day. Most RO filters can produce at least 50GPD.

But often, the actual capacity is 10-20% lower than the stated one. Thus, for large families we recommend systems with a daily capacity of 90-100 GPD.

Note that factors like source water quality, water temperature, and your water pressure will affect daily production capacity.

Capacity will be lower if the source water has a lot of impurities, if it’s cold (such as during winter) or if it comes in at a low pressure.

2. Number of Stages 

For the best filtration performance, get a system with no fewer than 4 filters: a sediment filter, a carbon filter, the RO membrane, and a post filter.

This not only removes more impurities from water, it also lengthens the life of the filters and especially the membrane.

Some systems also include a UV filter that provides extra protection from microbes.

3. Filtration Performance

It’s hard to determine a system’s performance without using it at home. So here you have to go with what other customers are saying.

Specifically, check by how much the filter reduces TDS or total dissolved solids.

A good RO system should reduce TDS by at least 90%.

Another indication of a high performance system is a certification from organizations like NSF and WQA.

Check the certification documents to see exactly which impurities the filter is certified as effective in removing.

4. pH/Remineralization Filter

The RO membrane does not filter out carbon dioxide and other gasses in water. The carbon dioxide forms weak carbonic acid.

To counter the acidity of RO purified water, some systems have a pH filter that adds stripped out minerals back to the water.

This increases pH to neutral or slightly alkaline.

According to some studies, alkaline water is healthier than acidic water.

Some people also find water with minerals sweeter and better tasting than completely pure water.

If you want to avoid drinking acid water or you love the taste of mineral water, look for an RO system with a pH filter.

5. Faucet Flow Rate 

All reverse osmosis filtration systems produce a weaker stream of water than that from your normal tap. But some are painfully slow, making it tedious to fill a large bottle or pitcher.

For large families, that consume a lot of purified water, the slow flow rate can be inconvenient. We recommend getting a system with a booster or permeate pump.

It significantly increases the flow rate.

Some systems such as those from Home Master also use larger fittings to increase flow rate.

6. Waste to Purified Water Ratio 

Check how much water the system drains. This is expressed in form of a ratio of wastewater to purified water.

The most wasteful systems have a 4:1 ratio, meaning 4 gallons are wasted for every 1 gallon of purified water used.

Pricier systems are more efficient, with some reaching rations of 2:1 or 1:1. Most of these low-waste RO filters have permeated pumps that greatly reduce the amount of water that goes down the drain.

7. Filter Lifespan 

Regardless of the price of the system, most RO membranes last 2-3 years.

What varies is the lifespan of the pre-filters.

Low capacity filters have a lifespan of 6 months, meaning you have to replace the filters twice a year.

To reduce maintenance costs, look for filters with a longer lifespan of at least 12 months.

8. Storage Tank Size 

Check how big the storage tank is. The smallest ones are about 3 gallons in capacity.

The best size depends on your family size and how much purified water you drink.

For larger families, look for a system that provide a storage capacity of at least 4 gallons. This ensures there’s enough purified water at any time.

Also, check if the system can be upgraded to a larger tank. Some tanks can be as big as 20 gallons.

Is RO Right For You?

best ro system

A reverse osmosis system is right for you if:

  • You want to purify your tap water, not just filter it. Only an RO filter can purify water.
  • You are concerned that your water contains heavy metals, chemicals and harmful microorganisms. An RO filter provides the best protection against biological contaminant as well as heavy metals and certain chemicals.
  • You want to reduce the level of total dissolved solids in your drinking water. A typical RO system can remove up to 90% of TDS including iron and hardness minerals.

A reverse osmosis filter is not ideal for you if:

  • You want a whole house water filtration system. RO systems are point of use, meaning they only treat water at one point such as the kitchen sink.
  • Your main concern is sediment in your water. A good quality sediment filter is good enough for removing sediment from water.
  • Your main concern is chlorine or chloramine. Get an activated carbon filter instead.

How to Install a Reverse Osmosis Water Filter System?

Most residential reverse osmosis water filters are designed for easy DIY installation. But while the setup process is fairly easy, it takes quite a bit of time.

Clear 2-3 hours from your schedule to give yourself enough time to install the system under the counter.

Here are the basic tools you need to have on hand.
  • Variable speed drill for making a hole in the sink for the new faucet.
  • ½” and ¼” drill bits - one for the faucet and the other for the waste line.
  • Adjustable wrench.
  • Philips screwdriver.
  • Scissors or a utility knife.
  • Teflon tape.

All the fittings including the faucet are usually provided along with the filter.

Here’s the general installation process. Check you user manual for specific instructions for your particular model.

  1. If the main filter system doesn’t come pre-assembled, start with that. Put the filter cartridges inside their housings and put an O-ring around the top. Tighten the filter housings in place on the filter system. Use the included wrench to tighten them but be careful not to over tighten. If your system comes pre-assembled, go straight to step 3.
  2. Connect the required tubes between different filters. Check your manual to know which tube goes where.
  3. Mount the filter system under the counter using the mounting kit provided. Some systems don’t need to be mounted; you just place it on the floor under the sink. Now you are ready to connect the system to your cold water line.
  4. Turn off the cold water line and drain the pipe by turning on the cold water faucet.
  5. Attach the feed water adaptor onto your cold water line. Depending on the size of your water outlet, you may need to use a converter before attaching the adaptor. Remember to wrap Teflon tape on the male threads before attaching the adaptor to prevent leaking.
  6. Install the saddle clamp as directed by the manual. This will require drilling a hole in the drain pipe.
  7. Place the storage/reserve tank under the counter and hand-tighten the shut off valve on it.Wrap some Teflon tape on the nipple threads before attaching the valve.
  8. Attach the quick connect tubes to the right valves and connectors as shown in your manual. There should be a tube running from the feed water adaptor to the filter system. Another from the system to the reserve tank and another from the system to the drain saddle.Most RO systems come with color coded tubes to make it easier to know which tube goes where.
  9. Drill a hole in the sink or counter for the faucet. If your sink already has a hole, no need to drill a new one.
  10. Attach the faucet and connect the right tubing coming from the post-filter.
  11. Turn on the water and check for leaks.

You’ll need to flush the system before you drink the water. Let the reserve tank fill up then drain it by opening the faucet. Do this a second time.

After that, you can drink the purified water.

Note: If you have a countertop RO system, it’s much easier to install. You just need to remove your faucet aerator and attach the adaptor. Connect tubing to the adaptor to take water to the RO filter. Finish by connecting the drain line that will drain wastewater into the sink.

Countertop systems have their own water outlets so there’s no need to install a new faucet.

How to Change Filters & Maintain a Reverse Osmosis System

Maintaining your reverse osmosis water filters mainly involves replacing the filters once or twice a year.

If you have a Home Master system that uses a modular design, replacing the filter is very easy. Just remove the current filters and put in new ones.

If your system uses cartridges, first remove the filter housings using a filter wrench.

Remove the cartridges inside, wash the housing with mild soap, put in a new cartridge, and tighten the filter back onto the system.

Note: Turn off the cold water line before changing filters.

Removing the RO membrane is just as easy. Unscrew the membrane housing and remove the used filter inside.

Wash the housing and put in the new membrane, taking care not to touch it to avoid contamination.

When to Replace Reverse Osmosis Water Filters

Filter Life Indicator

Most RO systems don’t come with a filter life indicator or a replacement reminder. The manufacturer will simply recommend changing the filter every 6 or 12 months.

But your filters may last for longer or less time depending on your water quality and consumption.

To avoid replacing your filters too early or too late (which could damage the RO membrane), get a TDS meter.

Measure the TDS levels in your tap water and purified water.

The purified water should have TDS levels 10% those of tap water. If the purified water TDS approaches 15-20% the TDS of tap water, replace the pre-filters.

Note: If your system has a pH filter/remineralization stage, TDS levels of the purified water will be a bit higher. Take a reading when the filters are new and measure future readings against the initial one. If TDS levels start going up, you know it’s time to get a new filter.

RO Filter Optional Accessories

One thing we love about reverse osmosis water filters is their modular design. A standard RO system consists of different components that you can remove or add to depending on your water treatment needs. 

The biggest advantage of this is that you can upgrade your RO system even after you’ve already installed it by buying various accessories. Here are the best ones. 

Permeate/electric pump

Adding a pump to your RO system increases the pressure of water through the filters. This increases filtration performance, flow rate, tank full-up time and reduces how much water goes down the drain. 

A permeate pump is non-electric and cheaper. An electric pump, though pricier, provides a bigger increase in water flow rate and bigger water savings. An electric pump is especially helpful for homes with low water pressure. 

UV Sterilizer 

If your RO system doesn't come with a UV filter, you can buy one separately and add it to the system. It’ll provide additional protection from microbes. 

Mineral Filter 

If you have a basic 5-stage RO system without a mineral filter, you can buy a mineral filter (from the same RO system manufacturer) and connect it to the RO system right at the end just before water goes to the faucet. 

Bigger Tank 

If the standard 3.2-gallon tank your RO system came with is inadequate, you can get a bigger pressurized tank. 

Tip: If you buy a bigger tank, we highly recommend also installing an electric RO pump (if you don't already have one) to ensure the tank fills up quickly. 

Fancier Faucet

The faucets that come with RO systems are good enough, but you can always replace it with a fancier one if you want. 

Water Leak Detector 

best ro system

This is one accessory we think everyone with an RO system should get. A water leak detector can save you from costly water damage. 

It’s easy to miss a leaky RO system because it’s hidden under the sink, until a small leak turns into a flood. 

There are two types of water leak detectors: auto shut-off valves and alarms. 

A water leak auto shut-off valve connects to the inlet water line and sits on the floor under the sink. Inside is a pad that expands if it comes into contact with water on the floor. This closes a valve, shutting off water flow and preventing further leakage. 

A water leak alarm doesn't connect to the RO system. It’s a simple device that you place where there’s likely to be a leak (in this case, on the floor under the sink). If it comes into contact with water, a loud alarm goes off to alert you. 

Some water leak alarms (like this one), have WiFi connectivity and can send an alert to your phone when there’s a leak. 

RO Systems and Hard Water: What You Need to Know

If you live in a hard water area, it is important to understand how the water affects your RO system and what you need to do about it. 

Generally, RO systems don’t go well with hard water. The RO membrane can remove the hardness minerals, but it’ll wear out quickly, requiring frequent replacement. The problem is that the hard water leaves scale on the membrane, making it harder for it to filter water. 

Over time, scale build up reduces the RO system’s filtration performance. You’ll get a slower flow rate and the TDS of the purified water will rise. 

Most RO systems can handle fairly hard water, up to 10 GPG. If your water is harder than that, we highly recommend installing a whole house water softener. 

A whole house water softener will also reduce iron in your water. Iron is another impurity that can make filtration harder for the RO system and reduce the lifespan of the filters and membrane. 

Frequently Asked Questions About Reverse Osmosis Water Filters 

best reverse osmosis system

Does a reverse osmosis water filter remove fluoride? 

Yes, it does.

Does a reverse osmosis water filter remove bacteria?

Yes, it does. It also removes viruses, cysts and other harmful waterborne microorganisms.

Does a reverse osmosis filter remove salt? 

Yes, it does. Most RO systems can remove up to 90% of dissolved salts.

How often should I change reverse osmosis water filters system? 

The pre-filters usually last for 6 months or 1 year. The post filter lasts about 1 year. The RO membrane lasts or 2-3 years.

Do I need to hire a plumber to install a reverse osmosis filter? 

Unless you are really busy, you can install an RO system yourself in 2-3 hours.

What’s the difference between purified and filtered water? 

Filtered water is not completely free of impurities. Normal filters remove only some contaminants. Purified water, the kind you get from an RO system, is almost completely free of impurities including microorganisms like bacteria.

Where do I install a reverse osmosis filter? 

Most are designed for undercounter installation though there are some you can set up on your countertop.

Does an RO filter remove healthy minerals in water? 

Yes, an RO filter will remove both bad and good minerals. If you want your water to still have good minerals, look for an RO system that replenishes healthy minerals in the water after purification.


best ro system for home

Reverse osmosis water filters are hands down the best types of water filters for homes. They can remove far more impurities compared to other types of the whole house, under-counter and faucet filters.

If you want the best protection for you and your family, an RO system is a way to go.

Our number one recommendation is the Home Master TMAFC-ERP Artesian RO System.

Ed Carmichael