Air Gap Faucets For Reverse Osmosis Drinking Water Systems

(See the Diagram At the Bottom Of This Page)

Air gap faucets for Reverse Osmosis systems dispense water just like standard non- air gap faucets, but have the air gap built into the base of the faucet. Air gap faucets are designed to prevent backflow by incorporating a "backflow prevention" method called an "air gap".

Air gap faucets have three connections on the bottom of the faucet. The center threaded stem of the faucet is the RO water inlet connector from the tank. This connection is the same on air gap faucets and non- air gap faucets alike, and can use 1/4" or 3/8" tube. There are two more connections on the bottom of air gap faucets. One large connector (3/8") and one small connector (1/4"). Use a piece of 3/8" poly tube to connect the 3/8" connection of the base of the faucet to the 3/8" inch drain saddle. Be very sure that there are no droops in the 3/8" drain line. Air gap faucets require a 3/8" drain line and a 3/8" drain saddle. The 3/8" line from the base of the faucet to the drain saddle is not pressurized, it will work by gravity, just like the sink drain. That is why it must be 3/8". The waste line from the Reverse Osmosis system is 1/4". The water pressure forces the water out of the system and it enters an air gap faucet via the 1/4" connector on the base of the air gap faucet. Internally, inside of air gap faucets the water enters a small chamber in the back of the faucet. The water enters at the top and falls into the larger hole and 3/8" drain tube in the bottom of the air gap. There is a hole in the back of the faucet the goes into the air gap. The hole is part of the air gap device. It must remain open and free of debris. A faucet without a hole is not an air gap faucet. This hole has waste water go into the top and out the bottom. Water drops past the hole into the 3/8" waste line. This water action creates noise that comes from the open hole in the back of air gap faucets. Air gap faucets are noisier than non- air gap faucets. Some homeowners object to the noise that can come from an air gap faucet. Non- air gap faucets are much quieter

Air gap faucets are required in some areas as a matter of local codes, not in other areas. You will need to check your local code to see if you are required to install an air gap faucet. In some locals you can install a inline check valve in the drain line for backflow prevention. This allows the use of a non- air gap faucet, thereby eliminating the noise associated with air gap faucets.

When code allows, the 1/4" waste water out of the system is connected to a 1/4" drain saddle installed on the drain pipe under a sink. This is also a very quiet installation. Air gap faucets can be installed as non air gap faucets by installing a 1/4" drain saddle. Remove the 1/4" waste water line out of the reverse osmosis system from the base of the faucet and attach it to the 1/4" drain saddle. Remove the 3/8' drain line from the air gap faucet and discard. See more on silencing noisy air gap faucets