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Most reverse osmosis systems come with everything you need to install and use the RO filter. But you can still improve or modify your RO system using accessories.
Some accessories, such as TDS meters help you improve or maintain water quality. Other accessories, such as permeate pumps, enhance the efficiency of your system. Others, such as faucets, are simply for aesthetics.
In this quick guide, we explain the most useful accessories for your reverse osmosis filter and recommend the best ones you can order online.
If you are yet to buy a reverse osmosis system, head over to our reviews of the best RO systems to find the right one for your needs.
Your RO system is already doing a great job cleaning up your drinking water. Reverse osmosis is the most effective water purification method.
But if you are not careful with maintenance and filter changes, water quality can deteriorate and put your family in danger of waterborne contaminants.
Water quality accessories help you maintain and even improve the quality of water from your RO system.
Here are the most popular water quality accessories.
A TDS meter test for the level of Total Dissolved Solids (TDS) in water. TDS includes both the bad stuff like lead and arsenic as well as healthy minerals like calcium.
TDS meters do not measure water quality. Rather, they test how well your RO system is working.
A good RO system should significantly reduce TDS levels to less than 50ppm. If a TDS meter shows readings higher than that, it is an indication that you need to replace the filters or RO membrane to maintain water quality.
TDS meters are cheap. You can snag one on Amazon for as little as $10.
Our top recommendation is the HM Digital DM-1 In-Line Dual TDS Monitor.
Unlike handheld TDS meters, the in-line HM Digital TDS monitor allows constant monitoring. It’s also dual, meaning it can take a reading from pure RO water and unfiltered tap water at the same time, letting you easily see the disparity between the two reading.
If you want to test the quality of your water, get a water quality test kit.
A TDS meter checks the total number of dissolved solids. A test kit looks for specific contaminants.
If, say, you are worried some bacteria is getting through the RO system, you can get a water bacteria test kit. The same goes for other contaminants like chlorine, nitrites, lead, and arsenic.
Some test kits can test for multiple contaminants while others test for just a single one.
Or maybe you just need to replace the filters.
One of the best water test kits is the NovoBlue 14-in-1 Home Water Test Kit. It tests for bacteria, lead, chlorine and other contaminants commonly found in tap or well water.
It is not essential (the membrane does a great job removing germs from the water), but it’s nice to have it in your system. It works with the RO membrane to neutralize and kill harmful microorganisms such as bacteria and viruses.
Because the UV filter is installed after the RO system, it deals with any microscopic bug that passes through the membrane.
If your RO system did not come with a UV filter, we recommend the 11W iSpring UVF11A UV Disinfection Water Sterilizer. It works with any RO system, not just those from iSpring.
Here’s a quick explainer on how to install the UV filter yourself.
One of the biggest downsides of a reverse osmosis filter is the amount of water it ‘wastes.’
Waste is not quite the word for it (hence the quotes) since the ‘wasted’ water does a crucial job flushing the RO membrane and carrying the trapped contaminants away. The wasted water is why you don’t need to replace the RO membrane for 2-3 years.
That said, your RO system could do with less waste and better output from the faucet. Here are some accessories that can help.
If your RO drain constantly gurgles – indicating draining water – even when you are not drawing RO water, the problem could be a faulty or missing shutoff valve.
A shutoff valve turns off incoming water from the RO filters once the reserve tank is full. Without a shutoff valve, any new incoming water would go down the drain.
If you think your RO system has a faulty shutoff valve or lacks one, this one from APEC water works well for any standard RO system.
A leak stop valve protects you from another common source of water wastage – a loose connection.
It’s easy to miss a leaky connector since the RO system is under the sink, out of sight. A leak stop valve acts as your eyes, monitoring the system for any leaks.
It does this by detecting moisture on the floor under the sink. If there’s a leak, a pad inside the valve expands, cutting off the water supply from the main feed valve and saving you a flooded floor.
The Express Water Leak Stop Valve fits into any standard under-sink RO system.
Here’s a quick video explainer on how to install the leak stop valve yourself.
The standard 3.2-gallon storage tank that comes with most RO systems is enough for most families. However, if you often run out of RO water and have to wait for the tank to refill, upgrade to a larger capacity tank.
You can upgrade to a 5.5, 11, 20, or 40-gallon tank.
Keep in mind that the higher the capacity, the larger the tank. Make sure you have enough space under your sink to put the tank.
Tip: It’s okay to put the tank on its side if you are short on vertical space.
This 5.5-gallon iSpring reserve tank is ideal for larger families that drink a lot of RO water.
The best way to reduce the amount of water your RO system wastes is by installing a permeate pump. It’s non-electric, so you don’t need to have an outlet under your sink.
A permeate pump uses brine/wastewater to reduce backpressure from the reserve tank. This allows more water to get into the tank and less of it to go down the drain.
A permeate pump can improve your system’s waste to pure water ratio from 3:1 to 2:1, saving you a full gallon for every gallon of purified water you draw.
The Aqua Tec ERP-1000 permeate pump is affordable and works with any standard reverse osmosis system.
A permeate pump reduces wastewater but doesn’t significantly increase output pressure (RO systems are notorious for slow-flowing faucets).
If you need an accessory that does both get a booster pump.
Unlike a permeate pump, a booster pump is electric. Hence it’s more powerful. This is why it’s able to increase the pressure of water out of the faucet, allowing you to fill a water bottle in less time.
On the downside, you may need to hire an electrician to add a power outlet under your sink if you don’t have one already.
Our top recommendation for RO system owners looking for a booster pump is the Aquatec 6800 Booster Pump Kit. It’s more expensive than a permeate pump, but it works better at improving your filter’s efficiency.
Refrigerator ice kits: Connect your RO system to your fridge ice maker or a dedicated ice maker. Ice made with RO water is clearer, safer, and better quality. Our top pick is the ICEK Ultra-Safe Fridge and Ice Maker Kit.
Extra tubing: If you have an RO system, it’s a good idea always to keep some extra tubing around. You never know when you need to install a new accessory that requires tubing or replace damaged tubing. Buy extra tubing from your manufacturer or get this affordable NEESHOW 15-feet tubing with ¼” quick connect fittings.
Connectors: It’s common for RO system connectors to break, loosen, or start leaking. It’s useful to have replacement connectors on hand. The NEESHOW kit we’ve mentioned above comes with several quick connectors.
Drain adapter: Most RO systems come with a drain saddle for connecting the RO system to the drain line under the sink. But it required drilling into the line. If you are not comfortable drilling, get a drain adapter. It allows you to drain RO water (as well as water from the dishwasher) through the garbage disposal. Our top pick is the Watts Premier Drain Line Plumbing Adapter.
The most visible part of an under-sink RO system is the faucet. If you think yours looks a bit too dull and generic, there are plenty of stylish upgrades available online.
Just make sure that whichever faucet you get is compatible with your RO system (1/4” size) and that it is lead-free.
Feel free to look around online, but we think the Water Filter Tec Brushed Nickel faucet looks pretty good.
It is compatible with any standard RO system, including those that use 3/8” fittings.
If you receive hard water, either from your municipal or a well, we recommend installing a whole house water softener in addition to an under-sink RO system.
But doesn’t reverse osmosis remove all minerals?
Yes, it does, but at a cost. Hard water is, well, hard on an RO system, especially the delicate membrane. It will reduce the filter lifespan, forcing you to replace filters more frequently.
This is not only tedious; it’ll increase your maintenance costs.
Read our reviews of the best water softeners for your home to find the right one for your needs.
None of these accessories – apart from the shutoff valve – are must-have.
But installing a few of them will improve your RO water quality, save you maintenance and water costs, and ensure you get more out of your reverse osmosis system.
You don’t have to install all of them. Just pick a few that you think will benefit you most.