Is It Hard to Install a Reverse Osmosis System? Find Out Here!

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Installing a reverse osmosis system might seem a little daunting, but it might be worth a try if you don’t want to fork out for a plumber.

Depending on your type of system, some installations will be easier than others, but the only one we would define as hard would be a whole house reverse osmosis system. Countertop and under sink models are not too complex to do at home.

Let’s find out more!

Key Takeaways

  • It is hard to install a whole house reverse osmosis system. Countertop models are very easy to install, and under sink units are not complicated but do require a little effort.

Is It Hard to Install a Reverse Osmosis System?

Is it hard to install a reverse osmosis system?

The answer to this question depends on the reverse osmosis system you purchase. For example, a whole house reverse osmosis system is not easy to install, but for the more common under sink models, it is not too hard at all if you can follow some instructions and have the right tools. Countertop models are the easiest and are often installation free, or simply hook right up to the kitchen faucet in 5 minutes.

Under sink models require a few more steps but are doable yourself at home too. The most challenging part of installing these is making a few extra connections and drilling into your sink/countertop and drain pipe.

Whole house reverse osmosis systems are the most difficult, and it is best only to attempt it yourself if you have some plumbing knowledge and are a pretty handy DIY person already, otherwise, call a plumber or RO installation specialist if it seems too complicated.

plumber installing reverse osmosis system under sink

DIY: What to Expect When Installing a Reverse Osmosis System Yourself?

  • Before attempting to install a reverse osmosis system, ensure you have watched a few instructional videos, read a few how-to articles online, and thoroughly check your manufacturer’s instructions.
  • It may be helpful to have a second person present for some tricky bits, like tightening the RO faucet.
  • Be sure to have your step-by-step list nearby and all your tools and towels ready. Get to know what all the components of your RO system are and look like before you begin.
  • Expect things to be a little cramped with the under-sink system. There isn’t usually a lot of space under there, and it can get a bit tricky trying to fit everything in without kinking or bending water lines.
  • Also, don’t forget to turn off the water supply when installing!

Professional: Who Installs Reverse Osmosis Systems?

If you don’t feel up for installing a reverse osmosis system yourself, that’s okay. Most trained plumbers will be able to tackle the under sink systems and probably the whole house systems too.

It is best to work with a plumber who has experience with your type of RO system, so be sure to ask when you call around for quotes or even speak to the retailer where you purchased the system from to see if they have any trusted installation specialists.

The cost will depend on the type of system you are installing, usually $150-400 for a standard under sink system and usually well over $500 for a whole house system.

Where Should You Install an RO System?

Again, this depends on the type of system you are installing. Countertop systems need to be on the countertop. Under sink systems can be under the sink, or some choose to install them in a basement or utility room and run a water line to the kitchen. This would probably require the addition of a delivery pump.

Whole house systems need to be set up near the main water line, usually in a utility room, garage, or basement.

Any system must be installed on the cold water line and not exposed to freezing temperatures.

Under the Sink

Most of these reverse osmosis systems go under the kitchen sink, as the tank needs to be close to the RO faucet to push water through. Ensure that you measure the space under the sink to know there will be room for the system, the tank, and any mounting, and also that there is enough room for you to maneuver around it to change filters and perform other maintenance tasks.

If there is not going to be enough space, then look at installing it in a nearby utility closet or basement.


Countertop units require little to no installation. Simply place it on your counter where there is access to the sink, then connect and secure it. It should take around 5 minutes.

Main Water Line (Whole House)

These are the most complicated RO systems to install, and unless you are quite an experienced DIY plumber, you may want to enlist the help of a professional. The installation often involves cutting your main water lines, and it isn’t something you want to mess with, as mistakes can be costly.

Whole house reverse osmosis systems are sometimes outside as they are large, but it is important not to have them where they are too exposed to the weather and elements. A garage or basement is a good idea.

How to Install a Reverse Osmosis System

If you are installing an under sink reverse osmosis system, it can be done in a few steps.

Tools & Supplies

You will need (at a minimum) the following:

  • The installation manual
  • RO module and water storage tank
  • RO faucet
  • New filter cartridges and the RO membrane
  • RO Installation kit with color-coded tubing, filter wrench, stop connector, tank valve, faucet connector, and drain saddle
  • A drill
  • ¼” (⅜”) (½”) drill bits. The size will depend on the faucet.
  • A screwdriver
  • A tubing cutter
  • A utility knife
  • An adjustable wrench
  • A few towels

Under Sink Reverse Osmosis System

Step by Step Instructions

  1. Measure the space under the sink before purchase to ensure there is enough room for the RO system to fit comfortably.
  2. Unbox the system and check that all components fit in their desired location.
  3. Turn off your water supply.
  4. Install the reverse osmosis faucet following the instructions (it may require you to drill a new hole in your kitchen sink or counter).
  5. Put the faucet through the hole and secure it from the bottom (this may require a helper!) Attach the quick-connect fitting and tighten it.
  6. Install the drain saddle above and away from the dishwasher discharge and garbage disposal. Drill a ¼” hole in the top or the side of the drain pipe and secure, aligning the clamp hole with the hole in the pipe.
  7. Install the feed valve that connects your RO system to the cold water line.
  8. Install the water tank within 10 feet of the RO faucet.
  9. Mount the RO module and connect it with the color-coded tubing.
  10. Install the filters and the RO membranes into their respective housing. Tighten with a filter wrench.
  11. Start the system and check for leaks. Wait 10 to 15 minutes for the water to dribble from the dispenser. Then close the faucet and allow the storage tank to fill.
  12. Flush all the water out once the tank is full to clear it of any fibers from installation, then let it fill again. Flush again if needed.

If you have any thoughts about the question, is it hard to install a reverse osmosis system, please don’t hesitate to leave a comment below!

About the Author Alexandra Uta

Alex is a content writer with an affinity for research and a methodical attention to detail. Since 2020, she has fully immersed herself into the home water treatment industry only to become an expert herself. Alex has been using water filters and similar products for years which has gained her lots of hands-on experience.
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