Hi Joseph...

Here's what the 2010 California UPC has to say on water hammer arrestors:

Section 609.10:

Water Hammer. Building water supply systems where quick-acting valves are installed shall be provided with water hammer arrestor(s) to absorb high pressures resulting from the quick closing of these valves. Water hammer arrestors shall be approved mechanical devices in accordance with the applicable standard(s) referenced in Table 14-1 and shall be installed as close as possible to quick-acting valves.

This suggests that water hammer arrestors should be installed at washing machines, dishwashers, ice makers and any other appliance/fixture with a solonoid or other fast-closing type devices/valves.

That being said, not all states using the UPC will require this as UPC is a uniform plumbing code but each state can amend as they decide.

For more information you will be best to call your local plumbing inspector and ask him about the specifics in your area, OK?

Any questions... let me know.

Mark

In my area, Standard Plumbing Code, we are mandated to install air chambers, (shock arresters) on each lavatory and the kitchen sink.
These are 1/2" pipe, 12 inched lone with a permanent cap. Regards, Tom

This means that you have to put it everywhere in the bathroom and also the kitchen sink?

How do would I know if something is a fast closing valve?

Joseph... I see you posted in the comments boxes. You need to post in the answer box at the bottom so your responses will show up in the thread... this sends an automatic notification to me and Tom so we know you responded (posting in the comment box doesn't send notification).

That being said, residential appliances that have fast-closing valves include: refrigerators (ice maker), dishwashers and washing machines. UPC does not require shock arrestors at sinks/shower valves as required by the SPC mentioned by Tom.

Remember to check with your local codes enforcement department for city/town specifics on this.

Mark

HI all, I'm under upc, and have never had an inspector call me for lack of shock arrestors in a residential system. Just don't see them in new building here. As Mark suggested, its best to ask your local authority having jurisdiction (plumbing inspector) what he will allow.