Hi-live in a 200 year old home (Victorian Beauty) just recently have an intermittent loud bang-help- nothing is leaking, water pressure is good-hope to get a sound reply thanks.

U may have air chambers in system that have filled with water.

Turn off main water supply. Open all faucets, starting at highest point. Drain toilet tank.

Under sink and toilet u have shut off valves. Remove bonnet nut and valve stem. Let water drain and reassemble.

Do this to each valve. Turn on main and shut all faucets.

Good luck

Chuck

Chuck nailed it! Let me take it a little bit farther. Back in the 60's we were required to to put air chambers on all bath lavatories and kitchen sinks. Over time water and condensate built up in them and they must be recharged. First turn off the house at the main house shut off valve. Then open hot and cold faucets at the farthest bathroom to prevent air lock.(This is important.) You will find under each fixture little brass or chrome valves. These are called angle stops. With a small pail held under the angle stop to catch the run off look under the handle of the stop and you will see a nut with the stem running through it. This is called the bonnet packing nut. Put your wrench on it and back it off counterclockwise. Now open the stop and remove the stem and washer assembly, The stop will began to drain. When it has quit draining reassemble the stop and move on to the next one. Do this on each one of your angle stops. There will be six of them in a two bath home. When you are done, close off the faucets you have opened, turn on the water to the house, and give yourself a pat on the back.
You have just recharged your air chambers and saved yourself a hefty service call bill. Hope this helps you out and thank you for rating my reply. TOM

Check all your shutoffs and make sure your pipes r supported

Im assuming you don't have the original plumbing(if you do, please let us know what it is, even if you don't, please let us know what type of water piping you have) Also, can you tell us exactly when the banging is taking place. Is it when certain fixtures are used. The more info here the better we can help.