: : will intalling hammer arresters (I was thinking of installing 3) where the main water supply enters the property(protected crawl space) do any good? Its much easier to intall there than at the appliance : YOU SHOULDNT NEED A HAMMER AT THE MAIN WATER SUPPLY. WHAT YOU NEED AT THE MAIN WATER SUPPLY IS WELL STRAPED PIPES. NOW IF YOU ARE GETTING A HAMMERING NOISE PIN POINT IT BY PLAYING WILL YOUR WATER FIXTURES. TURN THEM ON AND OF AND YOU SHOULD FIND THE RIGHT PLACE TO INSTALL A HAMMER. IT IS ALLWAYS A GOOD IDEA TO PUT A HAMMER ON DISHWASHER OR WASHING MACHINE. GOOD LUCK YOUR FRIEND THE PIPEXPERT…If you have the usual washer style taps, buy some brass stem ones. Flaten the stem so that you need to use a small hammer to drive the washer back into the tap body. This WILL stop the hammer at that tap. Then find the next problem tap