Saveourh2o is supported by its audience. When you purchase via our links, we may get a commission. Learn more

Reverse Osmosis Water Filtration System Installation

Writen by Ronald Brown

Fact checked by Natalie Bridges

reverse osmosis water filtration system installation

Reverse Osmosis is one of the most popular water treatment systems today because of its versatility, as it can produce superb potable water quality and prevent different types of microorganisms from entering your water supply.

But the question is, can we do a Reverse Osmosis Water Filtration System Installation at home? Definitely. Truthfully, we don’t have to be a Seasoned DIYer to finish this home project independently.

Browse through this comprehensive article to discover how to install a reverse osmosis system for your household water needs.

Table of Contents

What is a Reverse Osmosis System?


RO system installation often requires a 3-stage setup to produce clean and safe drinking water. The first stage is Prefiltration, which uses a screening or coarse filtration to pre-treat water: it includes activated carbon to strain and remove sediments, mineral deposits, and other large particles/debris.

The second stage is Reverse Osmosis itself, during which the pre-treated water begins flowing from a lower concentration to a higher one through the semipermeable membrane. In this phase, all suspended solids will be removed.

The last step is Drainage and Storage; purified water goes through the holding/storage tank where it is contained until needed. Then, the rest of the contaminants are flushed down the drain, leaving exceptionally high-quality water.

Reverse Osmosis is a type of purification technology that uses a pressure-driven membrane to remove foreign particles, dissolved solids, and bacterial contaminants from your drinking water.

Furthermore, Reverse Osmosis is known to remove chemical pollutants from water such as calcium and magnesium (which makes hard water), lead, arsenic, sodium chloride, fluoride, and many more elements that cause taste and odor problems.

RO systems operate at relatively high pressures, which force feed water to pass through the semipermeable membrane. This flow-through material usually has 0.0001 micron pores which reject and trap the dissolved solutes in the mesh.

This diffusion process leaves pure H20 behind. Reverse Osmosis can retain 95-99 % of organic and inorganic compounds from the water supply, making it popular among private homeowners and commercial industries.

How to Install a Reverse Osmosis System At Home?


Tools/Supplies Needed

  • Screwdriver
  • Tape measure
  • Drill
  • Drill Bits
  • Adjustable wrench
  • Pencil/Marker
  • Level
  • Hacksaw
  • Channel Lock Pliers
  • Teflon/Plumber’s Tape
  • Duct Tape
  • Center Punch
  • Drain Tee
  • Installation KitRO unit with complete fittings for under-sink installation

Step 1 – Find The Best System Location

Typically, we can install reverse osmosis system under sink, but it can also be installed in alternative remote areas such as the basement, garage, utility room, or wherever you have access to your water supply tank.

Pro Tip: Do not install your RO unit at places with freezing temperatures

Step 2 – Prepare the RO Unit

Now that you have found the right location to install reverse osmosis, it’s time to unbox and inspect the whole RO system devices to make sure that they will fit under your kitchen sink in the desired space where you wish to install them.

Check and test the fittings and plumbing accessories to determine if you need adjustments to your existing drain pipes or water supply lines. If there’s a need for adjustment, it is advisable to hire a professional plumber.

The RO system should be installed in the cold water line alongside the water softener if you have one at home. Please take note that remote locations need additional tubing to unite all of the components. Likewise, confined spaces require extra tubing to ensure that the unit will work accordingly.

Step 3 – Install the RO Faucet/Spigot

First off, check if your kitchen sink has an existing hole for faucets or sprayers. If there’s none, drill a hole carefully. Stainless steel and composite are the most common materials used for kitchen sinks. Regardless of the material, you have to drill with precautions to prevent chipping or scratching.

To create the faucet mounting hole, you need a 2-inch flat surface with 1¼ thickness to ensure that drilling will not obstruct anything from underneath the sink, such as cabinet walls, drawers, support braces, etc.

For stainless steel, use a marker and mark the center of the deck with a center punch and drill the pilot hole continuously until it becomes ½”.

For porcelain, you should place duct tape over the target area as it will hold the drill in place and prevent slipping. You must carefully drill the hole with a masonry bit through the porcelain.

Lastly, clean the sharp edges.

If your sink already has a hole, remove the chrome plate that covers the sinkhole. Then, mount the RO faucet with the hardware kit that comes with your RO unit. Make sure that there’s enough space for the spout to swivel.

Finally, feed the water line through the opening hole and connect the air gap (red tube) to the faucet before securing the faucet onto its housing.

Step 4 – Prepare and Set The Filter Tank Under The Sink

Before placing the RO storage tank under the sink, set up the tank connector, wrap at least six layers of Teflon tape around the threaded nipple of the tank, then screw the connector onto the tank. Position the tank under the sink or below the sink-top faucet.

Step 5 – Mount the Reverse Osmosis Assembly

Put markings on the wall under the sink for the hanger washer. Then, install the RO filter assembly using the level to ensure that the unit is aligned correctly. Allow 15 ½ inches of space from the unit to the floor to perform regular maintenance tasks.

Step 6 – Shut off the water supply valve and connect the water line

Turn off the cold water supply and start connecting the ¼-inch green tank water line to the tank valve and the outlet port of the filter. This line should be connected with the adapter tee, together with an insert, ferrule, and a nut.

Most water filters come with a ½ inch adapter that matches a ½ inch flex line, but it can vary depending on the manufacturers. Therefore, tubing arrangements depend on this. Typically, when you buy an RO unit, it often comes with a tube that works with the water supply and the canister filter.

Step 7 – Connect the other tubing

Connect all of the remaining tubings; follow the manufacturer’s instructions on this part since RO units require different setups.

There will be a tube from the last RO canister filter to the sink drain, another to the storage tank, and a tube from the storage tank to the dispensing faucet/spigot.

Pro Tip: You can run the excess length of the tubing to the cabinets for a presentable installation. Otherwise, you can trim the tubing to your preferred size for a tidier look.

Step 8 Install The Drain Tee

Fit the drain tee on the existing drain pipe. Make sure that it fits snugly, and then mark the pipe. Cut it down using a hacksaw. Attach the drain tee fitting onto the pipe using the hardware provided (slip washers, nuts).

Step 9 – Test The System

Perform a pressure test. Turn the water supply valve back on and open the tap water from the kitchen sink. Kindly wait for at least 2 hours to fully repressurize the whole system.

After that, inspect the plumbing installations and tighten any loose fittings. Leave the faucet open and allow it to purge for 24 hours.

This is the last stage of Reverse Osmosis system installation, and you want to make sure that the filtration performance is immaculate; keep the system running for a day and look for any possible leaks. If there are no leaks, then you got it right!


Everyone wants pure and fresh-tasting drinking water. But homeowners are often discouraged by the daunting and complicated process of water filtration technologies. That’s why most of them seek help from professionals.

But after discovering the DIY hacks for Reverse Osmosis Water Filtration System Installation, I bet you can now do the procedures yourself. You just learned an incredible skill essential for your hydraulic system at home. How was today’s topic? Voice your thoughts in the comment box below!

5/5 - (2 votes)