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An under sink water filter is the best choice if you need to treat water for drinking, making coffee, cooking and other kitchen activities.
In this buying guide, we review the best under sink water filters for removing a wide range of chemicals and impurities from water you use to drink and wash dishes. We also explain how to install and maintain an under sink system and provide answers to frequently-asked questions.
Undersink water filters are point of use filters, meaning they treat water at a specific access point in your home - usually in your kitchen.
Pitcher water filters and faucet water filters can be used in lieu of an under counter water filter, but you'll generally get much cleaner water with an under sink unit.
OUR TOP PICK
3 stage filter
18 x 12 x 10 inches
BEST REVERSE OSMOSIS FILTER
6 stage filter
14.5 x 5.2 x 19.5 inches
BEST HIGH CAPACITY FILTER
3 stage filter
4.5 x 4.5 x 15 inches
BEST SMART FILTER
3 stage filter
4.2 x 12 x 12.9 inches
Home Master TMHP
MOST WATER-EFFICIENT RO
7 stage filter
12 x 16 x 20 inches
BEST CERAMIC FILTER
4 stage filter
3.5 x 3.5 x 12 inches
It consists of 3 stages of filtration, two of which use activated carbon blocks to completely remove chemicals and odors from your tap water.
If you don’t want to spend a lot of money on an expensive reverse osmosis (RO) system but want the same level of filtration performance, I highly recommend this filter.
It is easy to install – no need to spend more money on a plumber. It even comes with most of the tools you’ll need.
The main complaint from customers is that the instructions are a bit confusing. But since installation is straightforward, you won’t have much trouble understanding which part goes where.
3-stage filtration: The first stage consists of a sediment filter that removes rust, sand and dust from the water. The polypropylene filter has an extended dirt-holding capacity to increase lifespan. The other two stages consist of activated carbon that removes chlorine taste and odor, cloudiness and chemicals.
12+ months filter lifespan: For an average family, the filters can last 12 months or more. This reduces the number of filter replacements you have to make, which saves you time and money.
Fast water flow: The water pressure from your faucet doesn’t suffer noticeably even with the three stages of filtration.
Double carbon filters: Having two carbon filters increases filtration performance, ensuring your water is cleaner, healthier and better-tasting.
Easy installation: Most customers had no trouble installing the unit under their sink. The instructions are a bit fuzzy but you’ll figure out everything in no time.
The APEC WFS-1000 does not remove dissolved solids from water. These include hardness minerals like calcium and magnesium and metals like iron.
If your water is hard, you’ll have to get a separate under-sink or whole house water softener.
If you’ve been seeing rust deposits on your utensils and surfaces, you’ll have to look for a water filter specially designed to remove iron.
This makes the APEC water filter less than ideal for use in homes that receive well water.
Avoid this one if: You receive well water. It contains dissolved solids that this filter cannot remove. It’s also not ideal if your main concern is bacteria in water. The filter does not remove or kill microbes.
This filter is great for anyone looking for a high-performance and easy-to-install under-sink water filter to remove chlorine, sediment and chemicals from their tap water.
Ceramic filters like our favorite, the Doulton SuperCarb, offer several advantages over conventional activated carbon filter systems.
Like carbon filters, ceramic filters do not add chemicals to the water.
However, unlike carbon filters ceramics also remove bacteria, viruses and cysts from water making them especially good for cleaning drinking water. They also last longer than carbon filters and can be cleaned and re-used.
Doulton is the leading manufacturer of ceramic filters, and the W9330958 SuperCarb is our favorite ceramic filter for under-sink installation.
An installation kit is included though depending on your particular plumbing situation, you may have to buy a few extra parts.
Ceramic filtration: Though it doesn’t remove water-soluble solids, the ceramic candle filter is highly effective at catching dangerous bugs including cysts and bacteria.
Great for drinking water: A bit of a chlorine taste in your drinking water is unpleasant but harmless. E. Coli or Cholera on the other hand can be deadly. A ceramic filter can remove these microbes, ensuring your drinking water is safe for the whole family.
Integrated carbon filter: Luckily, you don’t have to endure the taste and odor of chlorine, harmless as it may be. That’s because this filter has an integrated activated carbon block that removes chlorine and various chemicals from the water.
Easy and quick installation: Installation is straightforward. Most customers set up the filter easily enough on their own. The manual has clear and easy to understand installation instructions.
Long lasting filter: The manufacturer says you can wash the candle filter with a brush and reuse it. You won’t have to buy a replacement for quite a while.
Self-sterilizing filter: Bacteria buildup on the filter can compromise your water quality. To make sure this doesn’t happen, the SuperCarb candle filter contains silver. Silver is naturally anti-bacterial.
This filter is not ideal for well water. That’s because it cannot remove hardness minerals or dissolved metals (collectively called Total Dissolved Solids or TDS).
The ceramic filter can only remove bacteria, viruses and cysts while the integrated carbon block is only good for chlorine and certain chemicals.
The other issue several customers have pointed out is that you most likely will have to buy some extra parts to finish installation.
Avoid this one if you receive well water. This filter will not remove hardness minerals, rust and other dissolved solids.
This filter is great for anyone wants to filter their drinking water but doesn’t want to buy an expensive reverse osmosis system.
Bottom-line, this Doulton ceramic filter works almost as well as a reverse osmosis filter in removing harmful bacteria and viruses from water.
The CuZn UC-200 turns cloudy, chlorine-tasting and chemical-laden water into clean, clear and safe drinking water.
This filter is designed to clean about 50,000 gallons of water - about 5 years of use - before you need to replace it.
The UC-200 uses three stages of filtration, all contained in one cartridge. This makes installation easy and ensures the filter does not affect your faucet’s water pressure.
Note: this system is larger and heavier than it looks in the images. Measure carefully, because you may have trouble fitting it under your sink.
Bonus: verified customers on Amazon praise the company’s customer service as much as the product.
3-stage NSF-certified filtration: This under-sink filter consists of three stages. Micro-sediment membranes remove small particles of dust, rust and silt. A Coconut Shell Carbon filter removes chlorine and chemicals. A KDF-55 filter removes heavy metals like lead and inhibits the growth of bacteria and mold.
High capacity: The CuZn UC-200 has a surprisingly high capacity for its price. It can filter up to 50,000 gallons of water, which translates to about 5 years for an average family. No hassles and extra expenses replacing the filter every few months.
DIY installation: There is no need to hire a plumber to set up this under-sink filter. The instructions are very clear and easy to follow. They also have an installation video on YouTube.
You don’t need to install an extra faucet for this filter. It connects directly to your cold water line. All the parts you need are included in the package.
The only tool you need to have on hand is an adjustable wrench to tighten the connections.
Excellent customer service: The almost-perfect rating is not because the filter is flawless. It has a few issues and there were several complaints from customers. But the company’s handling of complaints is amazing.
If you encounter any issue, they’ll give you a refund, send you a new unit or do whatever it takes to help you solve it.
It’s nice to see such high quality customer service from a major manufacturer.
The main issue with this unit is its size. It’s bigger than most people expected, making it difficult to fit it under the sink.
But most customers were eventually able to install it.
As for other limitations, this filter cannot handle well water. None of the three filtration stages can capture dissolved solids found in plenty in well water.
Avoid this one if you receive well water. This filter cannot remove iron and other dissolved solids found in well water.
This filter is great for anyone who needs a high-capacity water filter they won’t have to replace for years. It’s also great for large families, restaurants and cafes where water consumption is high.
The Aquasana AQ-5300 combines an excellent 3-stage filter with connectivity to a smartphone app that lets you track the number of gallons filtered and sends you filter replacement reminders.
The filter itself is a 3-stage system that can handle a wide range of contaminants except dissolved solids and water-borne bacteria.
3-stage filtration: Stage 1 consists of a 20-micron pre-filter that catches sediment, rust, silt and dust particles. Stage 2 is an activated carbon filter that removes chlorine and a variety of other chemicals from water. Stage 3 consists of a catalytic carbon filter that reduces chloramines and heavy metals.
Dedicated faucet: You’ll need to install a dedicated faucet for the Aquasana filter. But at least it’s included in the package. All you need to do is drill a hole in the sink and install the faucet. You have three finish options for the faucet to match your home décor: oil-rubbed bronze, brushed nickel and chrome.
Easy installation: Installation takes a bit more time than other filters because of the faucet. But you don’t need to hire a plumber.
The instructions are very clear. As long as you have the right tools, it takes about an hour to have your filter ready and the new faucet running.
If you are planning to use this filter to treat drinking water, note that it does not remove bacteria, cysts and viruses.
So make sure your water is already safe to drink. If you are concerned about these bugs, I recommend a reverse osmosis, UV or ceramic water filter.
Another limitation is that the Aquasana AQ-5300 does not remove most dissolved solids. So it wouldn’t be effective on well water.
It’ll only help with sediment and some chemicals but will not remove iron, manganese and hardness minerals like calcium.
Avoid this one if you receive well water in your home. It is also not the best choice if you want to neutralize bacteria and viruses in your drinking water.
This filter is great for anyone looking for a high-performance under-sink water filter that can remove chlorine, chloramines and a wide range of chemicals.
The iSpring RCC7AK-UV combines the water purification of Reverse Osmosis with the biological-killing power of UV light to provide the purest possible drinking water.
Reverse osmosis is one of the most effective ways to filter-out bacteria, viruses, hardness minerals, heavy metals, rust, chlorine and a wide range of chemicals. But still, some small viruses and bacteria can still get through RO filter media.
Adding UV filtering after the RO filter kills any remaining biologicals and prevents them from entering your drinking water.
So if you are looking for the absolute purest and best quality drinking water, I highly recommend buying this iSpring under sink water filter system.
The RCC7AK-UV is more expensive than other picks on this page, but it provides unmatched filtration performance.
High-performance RO filtration: RO systems are the gold standard for water filtration. No other filter matches their performance. According to Aquasana, their system can remove 99% of over 1,000 contaminants including lead, bacteria, chlorine, sodium, arsenic and fluoride.
Stage 1: A sediment pre-filter to remove rust, sand, dust and other particles. This filter is see-through to allow you to easily monitor accumulated sediment.
Stage 2: A carbon GAC filter removes chlorine, odors and cloudiness from the water. It also ensures chlorine doesn’t reach the RO membrane, which could damage it.
Stage 3: CTO filter removes chloramines, chemicals and VOCs.
Stage 4: The RO membrane, the heart of the system, catches any remaining contaminants.
Stage 5: A carbon post-filter removes remaining odors and tastes from the water.
Stage 6: pH filter restores water’s alkalinity and re-introduces beneficial minerals that were stripped out by the RO membrane.
Long lasting filters: The RO membrane has an estimated lifespan of 2-3 years. The other filters will last 6-12 months depending on how much water you consume. Replacing the cartridges is easy.
DIY installation: Even if you’ve never done any plumbing before, you can tackle this project in an hour or two. All the parts are included and you only need basic tools to set up the filter under your sink.
The system is more expensive than conventional under-sink filters, but it’s actually a bargain when you compare it to other RO filters that can cost $500 or more.
One downside you’ll just have to accept with any RO system is wasted water. It’s how reverse osmosis systems work.
All the trapped salts and contaminants have to go somewhere. The system flushes them out with water.
This particular system flushes 3 gallons of water for every 1 gallon you use.
That’s why RO filters are usually installed on just one tap. A whole house system would waste too much water.
Avoid this one if you are not concerned about chemicals and/or biologicals. If your main concerns are chlorine, taste/odor and sediment, then a less expensive 3-stage carbon filter will do just fine.
This filter is great for homeowners who want the highest-quality purified and biological-free drinking water.
Compared with the iSpring RCC7AK-UV, this Home Master is far more water-efficient, with only 1 gallon of water lost for each gallon consumed.
It is also more expensive.
Like the iSpring system, the Home Master filter includes a UV filter to ensure your drinking water is completely safe. In addition, it can handle well water without any problem thanks to the integrated iron pre-filter.
Multiple stages: This system targets almost all kinds of contaminants using different types of filters. There is a sediment pre-filter, an iron pre-filter, catalytic carbon to remove chlorine and chloramines, a UV filter to neutralize bacteria and viruses and an RO membrane to catch chemicals, bacteria and other impurities.
Ideal for well water: It’s hard to find an under-sink filter that can treat well water. That’s because most filters are not designed to handle the dissolved solids found in well water, particularly iron.
The Home Master system incorporates an iron filter that not only ensures rust doesn’t become a nuisance around your home but also protects the RO membrane from damage.
Mineral re-introduction: At the last stage, the system re-introduces beneficial minerals into the water by passing it through natural crushed marbles. This greatly improves the taste of the water.
High water flow: RO systems can be frustrating to use because of their weak flow. Home Master uses wider fittings that provide a stronger flow rate.
Less water waste: The Home Master system has a water waste ratio of 1:1. It wastes less water than most other RO systems.
This system is expensive. But considering the extra features and high filtration performance, it’s understandable why it costs more than standard RO systems.
The other issue is the long installation process. You can install the system yourself but you’ll need 2-3 hours to get it up and running.
Avoid this one if you are looking for a low-cost under-sink water filter. If you want a cheaper RO system, consider the iSpring unit above.
This filter is great for anyone who wants a high-performance RO under-sink filter that minimizes water waste. Also a better choice for homes that receive well water due to its built-in Iron filter.
Even if you get treated city water, it could still contain a variety of contaminants like sediment, lead and chemicals.
Some of these impurities may have gotten into the water on its way to your home.
For instance, if you have an older home build before 1986 when the government mandated lead-free plumbing, you might have lead pipes that introduce lead into your water.
The amount of contaminants is even higher if you receive well water. It contains lots of dissolved solids that harden water, cause discoloration of surfaces and can sometimes be harmful.
If you want water that you are sure is safe for drinking, cooking, pets, baby food and other household activities, then you need a water filter.
You could install a whole house water filter but that will cost you more and you might have to hire a plumber to install it.
Most people opt for a point-of-access under-sink filter that’s cheaper and easier to install.
Depending on the type of filtration media, an under-sink filter can remove lots of stuff from your water.
A type of water filter that’s installed under the sink. It connects directly to the incoming cold water line and provides filtered water through the existing faucet or a dedicated one.
A countertop water filter sits on the counter and connects to the end of the faucet rather than to the water line.
It’s a good choice if you don’t have much space under the sink.
While they do require some space on the countertop, most models are small enough for even the smallest kitchens.
On the downside, countertop water filters tend to have a lower flow rate than under-sink models.
That’s not a problem if you are only filtering water for drinking. But if you plan to use the filtered water for cooking, washing utensils and other activities, an under-sink filter is the better choice.
An under-sink filter is a point-of-access filter. You install it at a specific faucet.
A whole house filter is a point-of-entry filter. You install it on the main water line coming into the house.
Which one is the right filter for your home?
If you are solely concerned about using filtered water for drinking and cooking, an undersink filter will save you a lot of time and money.
But if you want also want filtered water for washing and bathing, then you’ll need to step up to a whole-house filter.
Note: Many homeowners use both types of filters, for example a single RO under sink filter in the kitchen for drinking water plus a less-expensive/no-RO whole-house filter to remove sediment, chlorine and chemicals .
Easiest to install, hidden from view.
The filter connects directly to the main cold water line and the filtered water is directed back into the existing faucet.
So you don’t need to install a dedicated faucet for the filtered water.
The main downside with this filter is that you have to install two of them if you also want to filter the incoming hot water.
Widest range of options.
The filter connects to the cold water line and the filtered water is directed to a dedicated faucet. That means you have to drill a hole in the sink for a new faucet.
Similar to a simple water filter, a conventional filter serves only one water line. If you want to filter both the hot and cold water, you have to install two separate filters and two separate faucets.
For the purest drinking water possible.
Most water filters use activated carbon to remove chlorine and chemicals from water. But activated carbon does not remove bacteria and other harmful water-borne bugs.
A reverse osmosis filter removes a wide range of impurities including chemical, heavy metals and dangerous microorganism including bacteria, cysts and viruses.
A typical under sink water filter uses multiple filtration stages is a specific sequence, usually from larger mesh to finer mesh filters. Each stage targets a specific type of impurity.
The first stage usually consists of a large-mesh / 100 micron sediment filter to remove large particles like dust and silt from the water.
The second and third stages usually consist of smaller-mesh carbon filters that capture molecules of chlorine and other chemicals.
In an RO filter, an even finer mesh RO membrane comes next to remove whatever other impurities and microorganisms the other filters missed.
Many RO filters also incorporate an alkalizing/water ionizer stage where the pH of the slightly acidic water is increased and lost minerals are added to improve taste.
Finally, some systems finish the filtering process by adding a UV filter to kill any remaining small organisms that survived earlier stages.
Here’s what to consider when buying an under-sink filter for your home.
A high quality under sink water filter will have at least 2-3 stages. The more stages the water goes through, the purer it becomes.
The most expensive RO filters use as many as 9 stages.
Modern carbon filters are extremely good at removing contaminants from water. If your water is generally clean, then you don’t have to buy a pricey RO filter.
But if you are concerned about removing all chemicals and bacteria from your drinking water, then an RO filter is the best.
If you don't like reverse osmosis or the water waste that comes with it, the consider buying a ceramic filter. It’s cheaper and can neutralize most harmful bacteria and viruses from water. But it should be paired with a carbon filter to make sure all chemicals are removed.
Most under sink filters involve very simple DIY installation. Some may take longer than others to set up but you rarely need to call a plumber.
Check that all the connectors and hoses are included. Installation will take longer and cost you more if you have to run to the store to get missing parts.
Also make sure the filter can actually fit under your sink before you order.
If you are buying an RO system, don’t expect the same water pressure as before. RO systems are slower and the thin tubes significantly reduce water flow.
But this is not a major issue if you are only using the filter to treat drinking water. It doesn’t take forever to fill a glass even if the pressure is low.
However, newer RO systems such as the Home Master one we have reviewed use wider tubes and special filter designs to increase water pressure without compromising filtration performance.
Carbon filters generally have higher flow rates. They are better if you need filtered water for higher-water-volume activities like washing dishes.
Most manufacturers list filter capacity in terms of months or years.
Most carbon filters last between 6-12 months while RO filters can last 2 years or more.
Some filters are rated in terms of gallons. But since it’s hard to track how many gallons of water you are using, you won’t know when to replace the filter.
Always look for the number of months or years of usage recommended by the manufacturer.
When buying replacement parts for your under-sink water filter, I recommend you order from the original manufacturer only. There are a lot of poor quality filters sold on sites like Amazon and Ebay today. So check those prices when making a decision.
Something else to check before buying is how easy it is to change the filter.
With most under sink water filter models, you simply unscrew the cartridge, remove the old filter and put in the new one.
In some models, both the filter and filter housing are one unit. So you have to replace all of them.
Depending on the type and size, you’ll need anywhere between 30 minutes and 3 hours to install an under-sink water filter.
Listed below is the general process. Check your user manual for more specific instructions.
Under-sink filters require almost no maintenance. Once you install the filter, check on it now and then to look for leaks.
After the manufacturer-recommended usage time, replace the filters are directed in the user manual.
An under-sink water filter removes chemicals and other harmful contaminants that are potentially dangerous for your health.
They also improve the taste of water by removing chlorine and chloramines.
It depends on the type of filter. A carbon filter will remove chemicals, chlorine and some dissolved solids.
An RO filter will remove a wide range of chemicals as well as water-borne bacteria, cysts and viruses.
Usually, no. Most under-sink filters require simple installation that you can do yourself.
Look for a filter specifically designed to remove dissolved solids like iron found in well water.
Not always. Some under sink filters work with the existing faucet.
In my experience, the best places to shop for under sink water filters in the United States is on major retail sites like Amazon.com, Walmart.com, HomeDepot.com and Loews.com. All of these retailers offer a good assortment of high-quality products at competitive prices.
When starting your journey, I recommend shopping on Amazon due to the variety and the quality of their reviews.
PRODUCT DIMENSIONS PRICE WEIGHT FEATURES SPECIFICATIONS
Doulton W9330958 SuperCarb
Under Sink Water Filter
3.5 x 3.5 x 12 inches $$$$ 3.2 pounds Ceramic filter / Genuine OEM product NSF Certified / ADA Compliant APEC WFS-1000 3 Stage
Under Sink Water Filter
18 x 12 x 10 inches $$$ 13.3 pounds US MADE super capacity filter 100% lead-free Chrome faucet / Plus NSF & FDA certified
CuZn UC-200 UnderCounter
4 x 4 x 15.5 inches $$$ 7.8 pounds 50000 gallons capacity KDF-55 Filtration Media and Acid Washed Catalytic Coconut Shell Carbon
3-Stage Under Sink
12 x 4.2 x 9 inches $$ 6 pounds Alerts you when it's time to change your filters Full system certified to NSF Standards
Woder 10K-GenII Ultra
High Capacity Water Filter
3 x 3 x 15 inches $$ 2.9 pounds Last for up to 10,000 gallons Built with NSF approved materials (NSF61)
4 x 6.8 x 14 inches $ 2.6 pounds 6 months or 2,000 gallons filter life Advanced Style
iSpring RCC7AK 6-Stage
Under Sink Reverse
Osmosis Water Filter
14.5 x 6 x 17 inches
$$ 20 pounds
Filter Cartridges with RO Membrane NSF/ANSI standard APEC Top Tier Alkaline
Mineral pH+ 75 GPD 6-Stage
Ultra Safe Reverse Osmosis Water Filter
16 x 5.2 x 17.5 inches
$$ 25 pounds
Premium long lasting filters Supreme quality Watts Inline
10 x 2.5 x 2.5 inches
$$$ 3.7 pounds
Lasts up or 20,000 Gallons NSF Certified for 20,000 gallons iSpring RCC7AK-UV Deluxe
Under Sink 7-Stage Reverse
Osmosis Drinking Water Filtration System
14.5 x 5.2 x 19.5 inches
$$ 31 pounds
NSF/ANSI standard resulting in WQA Gold Seal certification Home Master TMHP
Reverse Osmosis Water Filter System
12 x 16 x 20 inches
$$$ 18.75 pounds
Advanced long lasting filters upto – 2,000 gallons NSF (National Science Foundation) standards Culligan US-EZ-4 EZ-Change
Water Filtration System
14.2 x 9.2 x 8.4 inches
$ 4.05 pounds
Can filter up to 500 gallons of water Independently Certified by the NSF
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