: We have a 9 month old house and have only recently been getting a water hammer (about 10 in 5 seconds) about 4 times a day. This happens when no water is flowing. The system has a "Potable Water Expansion Tank" above the water heater, and a battery operated sprinkler controller under pressure. Where should I look?

: Thanks,

: Paul Ward
: San Jose, CA

Paul,
I would first check the toilets to see if the flappers are leaking. Terry