How to Install an Under Sink Reverse Osmosis System

Reverse osmosis systems are one of the most popular water filtration systems on the market. But most people don’t know how to install them properly, especially under the sink in their kitchen. So here’s a guide on how to install an under sink reverse osmosis system.


Can I Install a Reverse Osmosis System Myself?

Reverse osmosis systems are fairly straightforward to install. If you’re handy, you can tackle the project on your own. However, even if you’re not comfortable with plumbing work, it’s worth calling a plumber to ensure that everything is installed properly.

Here are the materials and tools you’ll need to install a reverse osmosis system:

  • A water pressure regulator
  • A fat wrench
  • Duct tape
  • An adjustable wrench
  • Two 1/2-inch couplings
  • Two 3/4-inch couplings
  • One garden hose adapter
  • One T-fitting for French drains or disposers
  • PVC pipe or copper tubing (3 feet)
  • PVC pipe (1 foot)
  • Two compression connectors (3/8-inch)
  • One compression connector (1/2-inch)
  • Pipe joint compound or Teflon tape

How to Install an Under Sink Reverse Osmosis System

If you want to install an under sink reverse osmosis system, you need to know a few key things.

First, make sure the area is well-ventilated because it will be pretty messy with all the water. You’ll need plenty of space for the installation. This includes making sure there’s enough room on your countertop and in your sink.

Next, find a plumber who has experience installing reverse osmosis systems. If you don’t have any luck finding one, bring them into your home by hiring one from a plumbing company! They can help you out with everything from installation to maintenance.

The last step is to set up your water piping correctly so that the water is able to flow through the system properly. A homeowner without plumbing experience might struggle with this part of installation, but it shouldn’t be too difficult for a professional plumber.

How Does an Under Sink Reverse Osmosis System Work?

An under sink reverse osmosis system filters out a larger quantity of contaminants from your water than a regular filter.

The process works by forcing water to go through a pre-filter, a reverse osmosis membrane, and another post-filter. First, the water goes through the pre-filter, which removes bigger particles that could clog up the membrane. Then, the water moves into the reverse osmosis membrane, which removes everything from oil to pharmaceuticals from your water. Finally, it moves through another post-filter to remove any remaining sediment before you get your clean, filtered water!

What Are the Benefits of Using an Under Sink Reverse Osmosis System?

The benefits are endless! The water is not only cleaner, but healthier. It removes harmful contaminants, without removing minerals that are essential for your body.

One of the best features about under sink reverse osmosis systems is the convenience. You won’t have to lug heavy bottles around all day. Just fill up a pitcher or a glass and you’re good to go!

Under sink reverse osmosis systems also help with household finances. You can save up to 10,000 gallons of water every year by installing one of these systems in your home! This means you’ll have much less monthly bills because you’ll be using less water from your utility company.

How Much Does It Cost to Install a Reverse Osmosis System Under Sink?

If you want to get a professional, installing a reverse osmosis system can cost anywhere between $1,000 and $5,000+.

The cost of installation will depend on your water pressure. If you have low water pressure, it will cost more to install the system because the process will take longer.

If you are in the market for an under sink reverse osmosis system, you should consider what type of filters are included in the system. Not all systems are created equal. Higher-end models include additional filters for fluoride, chlorine, and sediment—perfect for those who want to filter their water completely.

DIY - Reverse Osmosis Installation

Does a Reverse Osmosis System Need a Drain?

One of the most common questions people have about installing a reverse osmosis system is whether or not there needs to be a drain in the sink. The answer is no, but there are some pros and cons to using a drain with your filtration system.

If you use a drain, you will have easy access for cleaning the system. If you don’t, then you’ll need to go under the sink in order to clean it which might be difficult for some people.

The other main advantage of using a drain is that it can remove any sediment from clogging your system. Without one, you might find yourself spending more time cleaning out the sediment from your pipes and getting rid of bacteria growth.

On the other hand, if you do use a drain, it could mean an increase in pressure which could damage your home’s plumbing pipes. This is especially true if your house has old corroding pipes which may be at risk for bursting due to high amounts of pressure (which can occur when water passes through them at high speeds).

Is Reverse Osmosis Water Safe to Drink?

Reverse osmosis systems are typically used to remove minerals and impurities from water. This process leaves the water safe to drink and reduces the risk of health problems.

There are three types of reverse osmosis:

  1. Countertop reverse osmosis: These typically rely on gravity and pressure, but they cost more than under-sink units.
  2. Under-sink units: This type is about $300-$400 cheaper than countertop units. They’re also easier to install because you don’t have to worry about the plumbing pipes coming down from the sink.
  3. Compact RO systems: Compacted RO systems include a water filter and a tank all in one unit. They’re another $200 less expensive than under-sink units.

Can I Add a UV to My Reverse Osmosis System?

Yes! One of the best things you can do to enhance your water filtration system is to install a UV. The UV will kill any bacteria that are present in your water before it reaches your RO membrane.


There are many benefits to an under sink reverse osmosis system. It not only saves on space, but it also removes the need for water bottles and can provide cleaner water than a standard faucet. Installing an under sink reverse osmosis system is a must for any environmentally conscious person.

Meet the author: Robert Johnson

Robert Johnson is a professional kiteboarder, surfer, and lifeguard. He’s been involved in many different sports and has competed at the national level in multiple disciplines. Robert has been an avid comic book reader since he was a child and is now also a video game enthusiast. “I’m a geek and a nerd who loves to read, fish, and play video games. I occasionally write.” Learn more about Robert and the rest of the team.