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[FONT=Calibri][SIZE=3][COLOR=#000000]I have been experience banging pipes for a while now. Itseems as if it occurs when a toilet is flushed or a faucet turned on after anywater has not been used in a while. I worry that a pipe may break and I cannotafford to have that happen. I tried to drain my entire system to rebuild theair pocket, but that did not work. I installed air arrestors at my washer, butthat did not work either. Lastly, I checked the PSI at both a hose bib and at afaucet. At all points, I received a reading of 40 psi. I noticed just now, thatwhen the rattling occurs, water is leaking from the screw on the pressureregulator valve. Once the banging stops, the leak stops. Even though mypressure is good, could it be something in the regulator valve that has gonebad?[/COLOR][/SIZE][/FONT]
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Two types of banging in a water pipe.

The first is known as water hammer. Water hammer occurs when the water is abruptly turned off. That is, when a toilet fill valve abruptly shuts off or you quickly close a single lever faucet. Can also occur when a washing machine water solenoid valve closes. The sound is usually one or two loud bangs, sometimes three.
You should have air chambers at each fast acting valve. An air chamber is just a vertical piece of pipe (in the wall) that is capped off. It is a place where air can be trapped to cushion the sudden stopping of the water flow.

Water, especially water under pressure, will adsorb air. That means you have to periodically turn off the water and drain the pipes. You have to let air in for the pipes to drain. Open all faucets and flush all toilets. Disconnect the supply tubes at all toilets and all single lever faucets. The draining of the pipe will not pull air back in at these types of valves. Sometimes it takes some time for the air chamber to loose their vacuum and the water to drain. So leave your water off and you pipe open for as long as possible.


The other sound is more of a rat,a tat,tat,tat sound. This occurs when debris gets trapped in a valve or you have a loose washer in a valve. The debris or the loose washer causes a rapid stopping and starting of the water flow and caused the pipes to vibrate against a structural member. This can occur in the faucet or it can occur in the stop valve.

If a certain faucet or toilet causes this sound then the problem is in that faucet or toilet or the stop valve supplying it.

If this sound occurs at multiple faucets or toilets then most likely it is the main shut off valve to the house, or it is a defective PRV (Pressure Reducing Valve).