I was wondering if anyone might be able to help us with a water hammer problem. We live in a three-year-old house, and we hear a bang downstairs when our faucets in the upstairs bathrooms close and when our washing machine shuts off. Also, when our sprinkler system changes zones, we hear a loud bang. My husband replaced all of the sprinkler valves with "slow closing" valves, but the sound is still there. To fix the inside problem, he's tried draining the system to recharge the air chambers, and he's installed an arrestor or two, but nothing's really worked.

Does anyone have any ideas, especially for the sprinkler system? Is there a specific way to drain the system to recharge the air chambers? Our sprinkler system does have a backflower preventer, if that affects anything. Thanks for your help!