How To Install a Reverse Osmosis System

Reverse Osmosis System Installation Guide

Water is an essential part of our life and having clean and safe-to-drink water is a need. However, it would not be wise to keep bottles of water from the grocery store as it can be quite costly over time and is not environmentally friendly because these water bottles contribute to plastic waste and pollution.

One of the best solutions to this problem is using a reverse osmosis system. If you have already decided to buy one, you should be prepared to get it installed in your home. In this guide, we will take you through the necessary steps to install an RO system, and at the end of it, you will be able to install it on your own, without the help of a plumber.

Where to Install Your RO system?

Before you learn how to install a reverse osmosis system, it is essential that you decide where you want to install in your home. Installing reverse osmosis systems under the kitchen sink is the standard practice, even though it’s not the most convenient and ideal spot due to limited space.

Besides under the kitchen sink, you can also place your new reverse osmosis system in the basement, garage or a utility room. Just as long as you’re running a water line to the sink. Do note that you may need a delivery pump.

The important thing that you should pay attention to is the cold water line should be installed downstream of any other water treatment system like a water softening system. Also, it is crucial that the installation isn’t somewhere where freezing temperatures may occur.

How to Install a Reverse Osmosis System?

Once you’ve decided where you want to place the reverse osmosis unit in your home, it is time to set up your new under sink system. Not only are we providing you with a step-by-step installation process, but we’ll also take a look at the preparation you need to do for a successful reverse osmosis installation.


If you haven’t bought a new reverse osmosis system yet, you should check to make sure that there is enough space under your sink to accommodate the filter module and tank. You should also ensure that there is a cold water line that you can use as your feed source.

Once you receive your new RO system, unbox it and double check that all the components are accounted for and are able to fit into their desired location. As such, you will know if any adjustments to the pipes are required before you begin with the installation.

After checking the components, you should gather all the necessary tools and parts. To save you the frustration of searching for tools and parts, you should have everything lined up and easily accessed. Here are some of the necessary tools for installing RO systems:

  • Installation manual for your RO system
  • RO module
  • Water storage tank
  • Faucet
  • Filter cartridges and RO membrane
  • Installation kit with color coded tubing, filter wrench, stop connector, tank valve, faucet connector, and drain saddle
  • Power drill
  • Different sizes of drill bit (depending on the type of faucet used)
  • Screwdriver
  • Tubing cutter
  • Utility knife
  • Adjustable wrench
  • Towel

RO Faucet Installation

To get that clean and great tasting drinking water from your RO system, you will need to start by installing the RO faucet. First things first, you will have to determine where you want the faucet to be located, unless your sink already has an additional hole that you can use. Otherwise, you will need to drill a new hole in the sink or countertop.

By keeping convenience in mind, you should position the faucet at a spot that can be easily accessed. You should also note that a specific kind of drill bit may be required to avoid scratching or chipping, depending on the surface material.

To start off, use a center punch to mark the spot. Then, gently grind away the enough materials on the surface to securely hold the ¼” drill bit. After that, carefully drill a hole and go slower than usual when you are close to any metal. For a ⅜” or ½” hole, you should still drill a ¼”pilot hole first.

Once that’s done, proceed to remove any leftover chips that could potentially damage your surface and clean up the sharp edges. Finally, allow the faucet stem to go through the hole that was drilled and secure it from underneath using washers and a hex nut. Then, attach the quick connect fitting and use a wrench to tighten it.

When you’re done with this, you would have completed the most difficult part of setting up the system.

Install the Drain Saddle

The next part of this installation is to install the drain saddle, otherwise known as drain line adapter, on the drain line. The saddle/adapter is meant to be placed on top of and as far away as possible from your garbage disposal and your dishwasher discharge if you want to avoid clogging. By doing so, your RO system can also be protected from potential contamination and fouling. It should also be at least 6” above the p-trap.

Have a ¼” hole drilled in the top or the side of the drain line, but never the bottom, and have the drain clamps secured with bolts, while aligning the clamp opening with the one in the drain pipe. Be sure to not overtighten it.

Feed Valve

Next, get the inlet feed valve installed. This valve will connect your system to the cold water line. But first, you will need to turn off both the cold and hot water supply. If the valves are not working, shut off the water to your home completely.

After that, open the respective outlets to release the pressure in the water lines. Once you’ve done that, remove the tubing from the cold water valve. Then, fit the new feed valve in (you might need to use an adapter) and use a wrench to tighten it. Make sure you close it for the time being. Before you turn your water back on, connect the cold water tubing to the new valve first.

Water Storage Tank

The ideal spot for your water storage tank should be within 10 feet of the drinking water faucet. This ensures that no significant pressure is lost and you get a consistent flow of water. You should be aware that the tank can weigh over 25 pounds when fully filled with water.

Prior to putting the tank where you want it, wrap around the threaded port at the top with about 6 layers of Teflon tape first. After that, screw on the tank connector or tank valve. They should thread on without much effort and need to be hand-tight.

For your information, many systems have a storage tank next to them without giving up any filtration performance. This is especially useful if there isn’t enough free area in your kitchen cabinet.

Mount and Connect RO Module

When you’re mounting the reverse osmosis module, you might want to take into account that you are required to replace the RO membrane and filters and/or carry out other maintenance works every now and then. To put it plainly, there should be enough clearance under the system.

It is recommended that you use the color-coded tubing to connect the module. Most reverse osmosis systems also come with quick-connect fittings. All you need to do is push the tubes into their designated fittings as far as possible and you can test out the connection by trying to pull it back lightly.

Bear in mind, that if water residues are in the tube, it means that the manufacturer has tested the system, so be sure to keep a towel at the ready.

Yellow feed water line. Push this yellow line onto the feed water valve that was fitted previously on one end and be sure the nut is tightened to a half turn past hand-tight. Get the other end connected to the feed port of the RO module. Cut the line, if necessary, to avoid any tangles.

Green tank line. Connect the green line to the outlet port of the filter system as well as the tank valve.

Black drain line. You are to connect the black line to the drainpipe and the flow restrictor of the reverse osmosis module.

Trimming is necessary for the water to flow downhill without loops.

Blue faucet supply line. The blue line connects to the quick connect fitting of the faucet and to the post filter outlet port.

For a maximized water flow, we would recommend you to have trimmed connections. Also, have some extra tubing around as it can be useful if you decide to move your system somewhere else.

Installing the RO Filter and Membrane

Now that you’re near the end of the installation process for your new system, it is time to insert the different pre-filters and reverse osmosis membrane into their designated housings. You should carry out this step in accordance to the following instructions:

Remove the filter housing for the pre-filters and slot in the filter. Then, make sure the housing is screwed back on with the O-rings fitted. Make certain that it is tightened with the use of a filter wrench in a careful manner.
To install the RO membrane, have the housing cap removed and slowly slot the cylinder into the socket until it is completely in. Put the cap back on while making sure that the O-rings are fitted properly.

Starting the System

The last step before you enjoy clean and safe drinking water from your new system is to get it started, and here’s how:

Open the feed water valve and the faucet while keeping the storage tank valve closed. When air is leaving the system, you will hear gurgling noises.

Check every connection to make sure there are no leaks.

The water should begin to dribble out of the dispenser after 10 to 15 minutes. Do not worry if the first trickle of water appears to have a darkish color, it is just carbon fines being flushed out by the system.

Close the faucet and open the storage tank valve, allowing the tank to fill. This should take about 3 to 10 hours, depending on the water pressure and quality. Once it’s full, you won’t hear water running down the drain anymore. At this point, you will need to get the drinking water faucet opened to flush the entire system.

When the water is dribbling again, this means the tank is emptied and you need to switch off your faucets for refilling.

Flush a second time by opening your faucet.

Flushing the system 2 to 3 times is usually recommended by most manufacturers. When you’re done flushing, the setup is complete and can start enjoying filtered water.


Now that you’ve come to the end of this guide, we believe that installing a reverse osmosis system on your own will be easier than ever. However, if you still find it challenging, we would recommend you to get help from a plumbing expert. The last thing you want is to install your new RO system wrongly and risk damaging the entire system.


How much does it cost to hire a local plumber?

If you are not confident enough to install your own water filtration system, you can always seek help from the local plumbers. However, do expect them to charge you as they are providing a professional service. Here are the general costs for setting up your water filtration system:

Countertop water systems. This type of water filtration system normally doesn’t cost anything because they are designed to be portable and can be positioned anywhere with minimal effort.

Under sink water systems. The installation for an under sink water filtration system is not too difficult so it usually costs between $150 to $400.

Whole house water systems. It is tough to estimate how much it costs for the installation of a whole house water filter system because this type of system is usually more complex. Generally, the minimum price that you should expect is $500.

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