How to Install a Reverse Osmosis Water Filter System?

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Drinking water is an important habit every doctor reminds his or her patients when they make a visit to the hospital. Keeping your body well hydrated is one of the secrets to living a healthy happy life.

However, drinking water, is not the key, the main goal is to drink clean and safe water. Contaminated water will only make you ill or develop lifelong health conditions.

If you are not certain about the quality of the water that you offer your household for drinking, then getting a reverse osmosis system is your sure bet.

Acquiring the reverse osmosis system will guarantee safe and clean drinking water for your family regardless of the source. You can purchase one online or go to your nearby store to get one.

For the system to function properly, you have to be careful how you install it, following all the instructions given in the manual. Below is a guide on how to install a reverse osmosis water filter system.

Where to Install an RO Water Filter?

Where to Install an RO Water Filter?

There are two types of reverse osmosis water filter systems. The first is known as countertop reverse osmosis system. This type of water filter is easy to install. It is designed to rest on the countertops of your kitchen or on a flat surface on the floor. You do not need a lot of technique to install this type of reverse osmosis system.

The second type of reverse osmosis water filter system is the under-counter reverse osmosis system, also known as under sink. Unlike the countertop system, this type of water filter is placed under the kitchen sink. It is harder to install compared to the countertop reverse osmosis system.

If you have limited space under the sink of your kitchen, you can alternatively install the system in the basement, utility room or garage, where there is a running water line to the sink of your kitchen.

It is important to note that, wherever you choose to install your reverse osmosis water filter system should be on a cold line, but not where the temperatures are too low to cause freezing. In addition, ensure you install the water filter system downstream any other type of water treatment equipment, for instance the softening water system.

How to Install a Reverse Osmosis System?

How to Install a Reverse Osmosis System?
How to Install a Reverse Osmosis System?

Before buying your reverse osmosis (RO) System, there are a few major considerations you need to observe. The first is the space under your kitchen to ensure it can accommodate a filter module and a tank, and the second it to ensure there is a cold water line that will feed water to the RO system.

After buying your reverse osmosis water filter system, it arrives to you in a box. Read the instructions on the installation manual as you get ready to install it in your kitchen.

The installation process should not be very hard, everything will be outlined and explained in the installation manual, but just in case you feel the information is not adequate, you can get more directions and videos with a simple Google search online. Unbox the system as you inspect the RO system to ensure all the parts named in the installation manual are present and can fit in their specific locations.

Different manufacturers and reverse osmosis water filter brands vary. Also, the plumbing system in your kitchen may be different. Therefore individual steps on how to install a reverse osmosis system will vary from one house to another. The instructions given in this article, are general procedures.

Tools for RO System Installation

To avoid inconveniences once you begin the work, gather all the tools that you will to install the RO system. If there are things you need to buy, write them down so that once you are started, there is no stopping to go find a tool or two. Below are some of the tools that you will definitely need to install the RO system.

  • RO system installation guide
  • RO system module
  • Water storage tank
  • Faucet
  • Filter cartridges and the RO system membrane
  • Power drill
  • Screw drivers
  • A knife
  • An adjustable wrench
  • Tubbing cutter
  • Drill bit that suits the size of the faucet
  • Colour coded tubbing
  • Filter wrench
  • Drain saddle
  • Faucet connector
  • Stop connector
  • Tank valve
  • Towel

Steps for Installing a Reverse Osmosis System

Now it is time to get started on the actual work.

1. Faucet Installation

Steps for Installing a Reverse Osmosis System
Steps for Installing a Reverse Osmosis System

The first step is to install the faucet that will offer you safe, clean and better tasting drinking water. Check on your sink to see if there is an extra hole, probably covered by a chrome plate. If there is no extra hole, then you will need to create one yourself.

Pick the most convenient location for the position of the faucet, most preferably a flat surface.

Mark your best location to drill a hole with a centre punch, then gently grind away surface material to create enough space to accommodate the drill. When you are done drilling, clean the sharp edges and remove any metal and wood chips that could ruin the faucet stem.

Put the faucet stem through the whole and attach it from the bottom using a washer and a hex nut. Then fasten the connect fitting and tighten it with a wrench.

2. Installing the Drain Saddle

The second step is install the drain saddle, which is also known as drain line or drain line adapter. As you consider the specific location to install the drain saddle, remember it should be as far away as possible from the dishwasher discharge and garbage removal.

It should also be placed above any type of garbage disposal from either the dishwasher or the sink drainage system. This is to ensure there are no chances for clogging of the RO system and to protect it from any potential impurity and fouling.

To install the saddle, drill a hole in the side or top of the drain line, then fix the drain clamps with bolts, but ensure it is not over tighten. Make sure the clamp hole aligns with the hole in the pipe.

3. Installing the Feed Valve

The third step is to install the inlet feed valve which connects the cold water line to the RO system. While installing the feed valve, make sure the water supply, both cold and hot is turned off. If the valves for the water line are not operational, you can turn off the entire water system for your home.

Remove the cold water valve tubbing and install the new feed valve. Tighten the valve using a wrench and leave it closed. Connect the new valve to the cold water tubing, you may need an adapter to connect the two, then turn the water system on.

4. Water Storage Tank Installation

To maintain enough pressure, consider placing the water storage tank at approximately 10 feet distance from the drinking water faucet. In addition, while considering the location of the storage, remember the tank can weigh more than 25 pounds especially when it is filled with water.

Before pacing the RO system storage tank into position, you need to install the tank connector first. Apply plumber’s tape into the threaded top of the tank. Then screw the tank connector or tank valve. The connector is needed to be only hand tight and it should thread easily. Now place the tank in place under the sink.

If the space under the kitchen sink is small, you can get an RO system that will allow you to place the storage tank on its side without tampering with the filtration process.

5. Mounting and connecting the RO Module

When mounting the module, remember you will regularly need to perform maintenance tasks and change the filters. Therefore, ensure there is enough space under the sink for the system. You will use the colour coded tubing to connect the module.

Most RO systems are designed with easy to connect fittings and all you need to do is push the correct colour tube into their particular fittings as far as they can go. You can test if the connection is safe by pulling the tube gently.

The colour coded tubes are connected as below:

  • Yellow feed water line

On one end of the yellow line, push it into the previously installed feed water valve. Ensure the nut is tightened slightly past the hand tight grip. The other end of the yellow line should be connected to the feed port of the RO module.

  • Green tank line

Connect the green line on one end to the tank valve and the other end to the outlet port of the RO water filter system.

  • Black drain line

The black line is the drain line. Connect one side of the tube to the drain saddle and the other end to the flow restrictor of the RO module. To ensure water flows downhill and without loops, cut the line.

  • Blue faucet supply line

Connect the blue line on one end to the post filter outlet port and the other end to the connect fitting of the RO faucet.

It is important to note, that once you will need to relocate the RO system, you will need new extra tubing to connect the module.

6. Installing the filter and the RO Membrane

Installing the filter and the RO membrane means you are almost done with this process. Read the instructions given in the installation manual on how to install the different pre-filters and RO membrane into their housing. Most the RO systems have sediment pre-filter, carbon pre-filters, the membrane and the post filters that are installed in that sequence.

  • To install the pre-filters, remove the filter housing, insert the filter and screw back the housing using the O-rings. Tighten the filter housing carefully using the filter wrench.
  • To install the RO membrane, remove its housing cover and slowly push the membrane, which is cylindrical, into the socket until it is completely in. Afterwards, put the housing cover back on and make sure all the O-rings are tightly fixed.

7. Starting the RO system

Congratulations, you completed the installation process. Now it is time to start your RO system. Do a quick check up to ensure everything is correctly and tightly fixed to where it is supposed to be, then follow the steps below to start the system.

  • With the storage tank valve closed, open the cold water feed valve and the RO faucet. The gurgling sounds that you hear are just bubbles of air leaving the system, no need for alarm.
  • Check the connection to ensure there are no leaks. If there are any, close the water feed valve and the RO faucet and fix the leaks first.
  • After roughly 15 minutes, water will start to trickle into the dispenser. The water may trickle in with a darkish brown colour, which is as a result of carbon fines being washed away. Close the RO faucet and open the storage tank valve to allow water to flow into the tank.
  • Depending on the quality and the pressure of the incoming water, it will take at least 3 hours or at most 10 hours to fill the tank. As soon as the tank is full, water will stop to run into the tank, open the drinking water faucet to empty the water.
  • Allow the tank to refill again and flush the system by opening the faucet for at least 3 times before drinking the water.

With an installation manual, it is not very hard to install a reverse osmosis water filter system. If you need more information aside from what is provided in the manual, follow the guidelines above to successfully install your RO system. However, not everyone is comfortable and confident enough to fix an RO system on their own.

Some people are also too busy to buy into the DIY style of installing the RO system. If you, too, prefer to get a professional’s help to install the system, just contact local plumbers in your area. The first step is to read reviews online and getting cost estimate before choosing the right service provider.


This is George, the Aquaman, editor at AquaMantra. I'm a water quality analyst by profession, and used to work at one of the largest water bottler company.
1 comment
  1. Dear George, Thank you so much for “How to Choose the Best RO System.” We have been thrown into this lead situation and had no idea what reverse osmosis is let alone how to treat our water. Your information is invaluable.

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