Are Air Chambers Required in Plumbing in California?


California plumbers used to install air chambers next to hot- and cold-water valves to help eliminate the water hammer caused by the energy in flowing water pipes when a valve is shut off. The old method consisted of a simple standpipe on the feed line with a soldered cap atop it. The pipe contained air to absorb some of the energy of valve closure. Under California Plumbing Code requirements, standpipe air chambers are no longer allowed. Instead, plumbers must install water hammer arresters at any location that contains a quick-closing valve.

Water Hammer Arresters

  • Water hammer sounds like thumping or banging every time you turn a faucet off in your home. It happens when the column of water in the pipe that is flowing through an open faucet is suddenly shut off. The force of the moving column of water slams against the valve. Think of it much like a train that slams into a wall at full speed. This causes huge spikes in water pressure that over time damages valves and causes plumbing problems and leaks. Water hammer arresters silence noisy pipes by providing a chamber to release that energy into when the water is turned off.

Code Requirements

  • Though each county operates under California's Plumbing Code, which generally follows the Uniform Plumbing Code, each county manages and regulates its building requirements and may modify the codes. The 2010 California Plumbing Code under section 609.10 indicates that water hammer arresters be installed next to quick-acting valves in a building's water supply system. A quick-acting valve includes any valve that turns on from no flow to full flow. This includes the ice-maker feed valve, washing machine hot- and cold-water valves, dishwasher valves and any valves that are solenoid-actuated, spring-loaded or self-closing. This also includes locations where touchless faucets are installed.

Water Hammer Arrester Type

  • Water hammer arresters installed in California must meet the American Society for Engineering Education Standards ascribed under ASSE 1010 – 2004 under California Plumbing Code requirements. This includes the specifications required to make the device and its performance requirements. A water hammer arrester from any manufacturer that indicates it meets the American National Standards Institute or ANSI-ASSE 1010-2004 is suitable for use in California. Under California plumbing requirements, water hammers must also be easily accessible.


  • Water arrester hammers are installed on the hot- and cold-water supply feeds to a faucet or valve. The water hammer arrester is available in different styles and company brands. As long as the device meets the ASEE 1010-2004 specifications and performance standards, it does not matter what brand a plumber installs near your quick-closing valves. The best place to install them is after the junction with the main water supply line but before the valve itself.

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