Under The Sink
Under-The-Sink Reverse-Osmosis Water Filtration System
Our most prominent water filtration solution. With a direct connection to your plumbing, the Under-The-Sink system supplies pure water on tap whenever you’d like, without having to refill a tank or transport water bottles in and out of your home.
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While there are reverse osmosis systems that can be installed to treat all the water in the home, it is more typical for an under-counter unit to be installed beneath the kitchen sink where most of the water used for drinking and cooking is provided. The unit includes four or five separate filtration canisters, each of which filters a different group of contaminants, plus a storage tank that holds the purified water. A countertop spigot, separate from the house faucet, delivers the purified water when needed.
Although the physics of how reverse osmosis filtration works are complicated, installation is fairly straightforward but requires basic plumbing skills.
WORKING TIME: 3 hrs
TOTAL TIME: 1 day
SKILL LEVEL: Intermediate
ESTIMATED COST: $120 to $300
Planning the Installation
Before purchasing a reverse osmosis (RO) system, make sure there is enough space under the kitchen sink for the tank and filters. Take measurements of the available space—in a sink space filled with a garbage disposer or other items, an RO unit with its tank and multiple filters may be hard to fit.
Also, make sure you have an idea of what cold water source can be used. Most units come with a tee connection that taps into the 1/2-inch cold water supply line going to the faucet. Other RO units use a 3/8-inch flex line that comes down from the faucet. In this case, an adapter tee above the shut-off valve can be used to provide a source of water for the filter system.
Prepare the RO System.
Unbox the storage tank and filter components and double-check to make sure that they will fit under the kitchen sink in the desired locations. Test fitting all the components can let you know if adjustments to the drain pipes or water supply pipes will be necessary. If so, this work may require assistance from a plumber.
Most reverse osmosis systems go under the kitchen sink but they can also be installed in a remote location such as a garage or utility room, then be run up to the sink location. The filter system needs to be installed on the cold water line past the water softener if your home is equipped with one.
Remote installation does not take up any room under the sink, but it does require more work to install. You may also need to buy additional tubing to connect the components.
Install the Sink Spigot.
Install the filter's sink-top spigot first so you can get the lines down under the countertop before it gets too crowded beneath the sink. Mount the RO spigot to the kitchen sink deck or countertop with the hardware provided. Many sinks will have an existing knock-out opening that can be used for the spigot. Sometimes the knockout intended for a sink sprayer can be used for the filter's spigot. In the worst-case scenario, you can bore a new hole in the sink deck or countertop to hold the filter's spigot.
Feed the water line down through the opening and connect the air gap (red tube) into the faucet before locking the spigot down onto the housing.
Prepare and Position the Tank.
Before putting the RO tank into position under the sink, install the tank connector. Apply plumber's pipe seal tape onto the threads of the tank nipple, then screw the spigot connector onto the tank, making sure to avoid cross-threading. The connector only needs to be hand tight and should thread on easily.
Now, position the tank in place under the sink. Where feasible, position it directly below the sink-top spigot.
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Mount the Filter Assembly.
Remove the filter assembly cover and mark the locations for the hanger washers on the wall below the sink, using a level to ensure that the unit is straight. This assembly needs to be a minimum of 15 1/2 inches from the floor to allow enough room to remove the filters for maintenance.
Screw the hanger washers onto the wall at the marked location, then set the assembly on the washers.
Attach the Water Line.
The green 1/4-inch water line from the filter assembly now must be connected to the water supply line. Start by turning off the water supply.
How you make this first tubing connection can vary depending on your situation. Most filters come with a 1/2-inch adapter that will work fine if the sink faucet uses a 1/2-inch flex line. If the sink faucet uses flex tubes of a different size, however, you'll need to use an adapter tee to make the transition to the water supply tube running to the filter unit. The green supply tube is connected to the adapter tee with a nut, ferrule, and insert.
Connect the Other Tubing.
Tubing configurations will vary depending on the manufacturer, but typically they consist of a tube running from the water supply to the first canister on the filter unit (the prefilter), another tube from the last canister filter (the RO canister) to the sink drain, and yet another tube to the storage tank. Finally, there is a tube running from the storage tank to the spigot on the countertop. In some 5-stage systems, the storage tank water also goes through a "polishing" filter on its way to the sink-top spigot.
However, the tubing configurations can vary quite a lot, so always consult the manufacturer's instructions on the proper tubing connections.
When connecting the tubing, use the extra length of the tubing to your advantage and run it to the back of the cabinets or wherever necessary to allow for the cleanest installation. If possible, leave extra tubing in case the system needs to be moved at a later date. If you prefer, the tubing can also be trimmed to size for a more clean, uncluttered look.
For this particular reverse osmosis system, the yellow tubing runs to the storage tank, the blue tubing inserts into the RO assembly, and the black tube fits into the drain adapter. Before connecting the yellow tubing, follow the manufacturer’s instructions about sanitizing the system.
Connect the Drain.
For a whirlpool reverse osmosis system, a drain tee is included. Position the filter's tee fitting up against the existing drain pipe, then mark and cut the pipe, using a hacksaw. When making the cuts, make sure that the tee will fit tightly.
Connect the filter's drain tee fitting onto the drain pipe using the provided slip washers and nuts—the connections are made in the same way that a drain trap is assembled.
Push the filter's black drain tube into the adapter tee.
Perform a Pressure Test.
Turn the water supply on and open the cold water on the sink to get any extra air out of the pipes. The pressure will start to build up in the system; you will have to wait for about two hours to get full pressure. Once the system is pressurized, check all of the fittings and tighten any that are loose or leaking.
Before using the water for drinking, drain the system by leaving the spigot on and allowing it to empty out and purge completely for 24 hours. The water will be a slow trickle after the tank is empty. Leave it on for a full 24 hours, and continue to test for leaks during this time.
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Pure, clean water whenever you need it.
Introducing the remarkable solution: an endless supply of pure, clean water available at your fingertips, precisely when you need it.
No more worries about running out of bottled water or dealing with the inconvenience of storing them.
Imagine the convenience of having access to crystal-clear water directly from your tap, faucet, or any other water outlet in your home. Experience the joy of savoring every sip, knowing that you are consuming water that meets the highest standards of purity and cleanliness.
Embrace the freedom and simplicity of having pure, clean water available whenever you need it. Let us take care of the logistics while you focus on enjoying the benefits of staying hydrated and refreshed. Say farewell to the inconvenience of water bottles, and welcome the convenience of our revolutionary system into your home.
The most Premium Reverse Osmosis water filtration process on the market!
Just schedule a time and our professional installers will come to your home and install your system for you, no additional work from you needed
Protect yourself and your family with clean, healthy drinking water.
Make an investment into your health and longevity with the Hydromosis Under-the-sink reverse osmosis system.
Don’t take our word for it,
Here are some of our many satisfied customers!
I have been using the reverse osmosis water filter from Hydromosis for over a year now, and I can't express how satisfied I am with the results. The filter has completely transformed the quality of my drinking water. The water tastes so clean and refreshing, and I have peace of mind knowing that harmful contaminants are being filtered out. I highly recommend Hydromosis water filter to anyone who wants to ensure they have access to clean and healthy drinking water without the hassle of having to install the system myself!
- Laura, MD
The Hydromosis water filter has been a game-changer for my household. We were concerned about the contaminants present in our tap water, but this filter has provided a reliable solution. Since using it, the water in our home has been noticeably cleaner and better tasting. The filter is efficient, and we no longer need to rely on bottled water. Hydromosis has truly exceeded our expectations, and we highly recommend their water filter for anyone seeking clean and safe drinking water.
- Malcom, CA
The Hydromosis water filter has been a revelation for me. I've always been conscious of the water I drink, and this filter has given me peace of mind. It efficiently filters out contaminants and ensures that I have access to clean and safe drinking water at all times. The filter is sleek, compact, and fits perfectly in my kitchen.
- Kimmy, TX
The filter is durable and easy to maintain, and the customer service from Hydromosis has been exceptional. I confidently recommend their water filter to anyone in search of clean and healthy water.
- Archie, MD
The filter is highly effective at removing impurities, providing me with clean and refreshing water. I no longer have to rely on single-use plastic bottles, as I can confidently drink from my tap knowing that the water has been purified by the Hydromosis filter.
- Simon, CO
I can't express how satisfied I am with the Hydromosis water filter. It has completely transformed the taste and clarity of my tap water. I no longer have to buy expensive bottled water because the filter ensures that I have access to clean and refreshing drinking water right from my faucet.
- Anne, WA
The most premium reverse osmosis water filtration System.
The five stages of filter.
Extras & Accessories
Extras & Accessories
Countertops
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Water Dispenser
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Water Filters
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Custom Pumps
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