This is not an ad! Take the quiz and get custom recommendations!

What is a Reverse Osmosis Faucet and Why Do You Want One?

A water filtration system is necessary if you want to have clean, pure drinking water available in your home.

Under sink reverse osmosis systems are considered one of the best water filtration options and require a reverse osmosis faucet. Most systems come standard with a basic water dispensing faucet for free.

However, you also have options if you want a filter faucet that is designed to match your decor, want special features, or need a specific style.

Let’s why so many people are installing RO faucets.

reverse osmosis faucet water

What is a Reverse Osmosis Faucet?

A reverse osmosis faucet is a dedicated faucet that connects to a reverse osmosis water filtration system and provides the filtered water.

They are usually made of metal and consist of a base that is installed into a hole in your countertop, a lever or dial to turn it on and off, and a narrow, arched tube that dispenses water.

They are designed to be compatible with your reverse osmosis system and you install it next to your normal sink faucet. When you want drinking water, you use the RO faucet, and when you need unfiltered water, you use the regular faucet.

The faucet with your RO system may also be called a reverse osmosis spout, RO spigot, or RO water tap.

How Do RO Faucets Work?

Reverse osmosis faucets connect to a water line that leads directly to your water filter or to a filtered water storage tank and not directly to your unfiltered plumbing.

When you turn on this special filtered water faucet with the integrated lever or dial, it opens an internal valve and dispenses filtered water.

Most faucets provide similar water flow since they are designed to match the output of the water filters they connect to.

How to Install

Installation of a RO drinking faucet can be very simple or difficult depending on your existing sink setup.

Since most reverse osmosis systems are installed in the kitchen to access clean cooking or drinking water, we will assume you are installing there as well.

If your sink already has an existing hole for a soap dispenser, sprayer, or a covered blank hole, the faucet can be easily installed there.

If you don’t have any of those existing options, a custom sink, or another setup, you will need to drill a hole of the required size in the sink or counter for the faucet.

The faucet also requires a water line connection to the filtration system. The necessary tubes and other parts are included when you order a complete system.

Types of RO Faucet

There are two types of faucets used by reverse osmosis systems.

These are air gapped faucets and non-air gap faucets.

Both types are compatible with your reverse osmosis water filter, but have different use cases, pros, and cons.

Non-Air Gapped Reverse Osmosis Faucet

Non-air gapped is considered the standard and is the most common type.

They usually come for free in the items included with most RO water filter systems.


  • Lower cost
  • Less tubing
  • No noise
  • Easy and quick installation
  • Can use a standard sized hole in your sink that may already exist


  • It is possible but unlikely that dirty water can flow back into the reverse osmosis filtration system
  • May not comply with plumbing that which require air-gap faucets in certain areas. Be sure to check your local codes before purchasing.

Air Gap Reverse Osmosis Faucet

air gap faucet

An air gap faucet has extra parts to ensure that unfiltered water can never back flow into the reverse osmosis system.

These extra parts include:

  • Air gap window
  • Brine input link
  • Brine output line


  • Prevents dirty waste water from going back into the reverse osmosis filtration system
  • Passes all plumbing codes in areas that require air gap faucets
  • Can extend the lifespan of reverse osmosis filtration systems


  • Usually needs larger hole size in the sink or countertop
  • More tubing required
  • May lead to sediment clogging
  • Noisy
  • More difficult to install
  • Higher price than non-air gap faucets

Why are Air Gap Reverse Osmosis Faucets Noisy?

Gurgling sounds can be produced while using air gap RO faucets when the storage tank is refilled with water.

A hissing sound can be heard from the faucet.

Can I Replace an Air Gap with Non-Air Gap Faucet?

It is easy to install a non-air gap reverse osmosis faucet as a replacement for your air gap faucet.

This requires buying a 1/4″ drain saddle.

You just have to connect a 1/4″ waste tubing directly to the drain while switching from 3/8″ drain saddle to a 1/4″ drain saddle.

Be aware that local plumbing code may require an air-gapped faucet if you already have one.

Multi-Line Faucets

By default, RO faucets come with one line to connect with the filtration system. Some people also install other water processing systems such as a drinking water heater or alkaline water system. In these cases, you may need an RO faucet with 2 lines or a faucet with 3 lines.

Material and Design Options

reverse osmosis faucet
The Waterdrop RO Smart Faucet LED ring glows when water flows.

When you add an RO drinking water faucet to your kitchen sink, you have choices of size, style, color, quality, and finish.

No matter what you get, be sure it is lead free so that it does not contaminate your drinking water with lead.

Stainless Steel

Stainless steel RO faucets are the most common and often come for free with RO filtration systems.

Steel is very durable, corrosion resistant, and scratch resistant.

Chrome Finish

Faucets with polished chrome finishes are very shiny and bright but are prone to scratches.

Brushed Nickel Finish

Faucets with brushed nickel finishes are more stylish and may be a better match for your existing kitchen sink accessories.

Unfortunately, it can easily be damaged, or you may see a color change if you use harsh cleaning products on it.

Top quality faucet options with special finishes can be bought with a reverse osmosis system from the manufacturer or from 3rd parties.

Matte black, copper, and other variations can be found to match the common colors of standard kitchen hardware.

What Should You Consider When Shopping for a Home Faucet?

If you want to find the top home faucet to add to your water filtration system, consider these important factors in your search.


Depending on the quality and design of the faucet, its price could range from about $25 to several hundreds of dollars.

Remember that most RO filtration systems come with a free basic lead-free faucet that will match the average counter top.

An air gap faucet will usually cost more than a non-air gap faucet.

Flow Rate

The flow rate of the water can vary depending on the faucet valve but is more dependent on the size of the water line that connects the filters to the faucet. The common water line sizes are 1/4″ and 3/8″.

If the input valve on your faucet does not match the tube from the filters, you can get an adapter to change the tube size.

If you ever notice little or no flow of water, the problem is probably with your filtration system and not with the faucet itself.

Kitchen Color

Faucets come in many colors if you want one that complements your countertop or existing sink hardware. Chrome, copper, polished nickel, and black are all common color choices. However, most systems come by default with a shiny stainless steel faucet.


There are many brands distributing faucets in the market, so you can find the one that meets your standards.

In general, any of them should be fine if they are lead free and popular.


Lead free construction is a must if you search for a new faucet.

Obviously, quality usually comes at a higher price, so expect to pay more for a fancy water faucet.


With the evolution of powered tankless RO systems, there are now RO faucets with various “smart” features, including:

  • TDS meters
  • Electronic RO faucet valves
  • Touch screens
  • Child locks


Unfortunately, installation of the RO water filter tap can be one of the few tricky parts of installing an undersink water filtration system.

If you have a flush mount sink and a very hard or think countertop, you will need to drill a hole for the faucet to pass through. However, if you have a sink with an existing punch out hole or a soap dispenser you can remove, then you can plan for an easy installation.

Any faucet you get will come with the necessary mounting hardware and instructions. You may just need a drill and special drill bit or to hire some help if you don’t have a hole in your countertop already.

The Biggest Benefit of a Reverse Osmosis Faucet

drinking water from an ro faucet

Whether you need an air gap faucet or non-air gap faucet, prefer simple or elegant design, or have a small or large budget, the biggest benefit of an RO faucet is this…

Healthy, clean reverse osmosis water!

Since you only need an RO faucet to go with your reverse osmosis water filter, you’ve already invested in your health and can enjoy the benefits of less contamination in your water.