I have the whole house pipe hammer rumble in the pipes when someone uses the shower or the left sink of a 2 sink vanity in the bathroom. It just started a few days ago and it comes and goes. I do have a small drip from a bathroom faucet. I have read about washers and something to do with a valve? I'm a decent novice plummer. I built on to my house and I added a new kitchen, bath room and a wash room (with hot water heater) by myself a couple of years ago(yes the problem is most likely from the part that I added). It was all trial and error and it was all self taught. I need some professional advice on this one.
Is caused by the abrupt turn on/off of the water and the resulting hydraulic pressures created. Improperly secured pipes can also make the effect worse. Go down to the local home store and ask about water hammer arrestors. Can add them to the problem areas and should help/eliminate the problem. Also can buy them thru the web. Use a Google search and you'll find many types.
Quick Easy short term fix, shut off the main water supply and from the lowest faucet drain your system and make sure all your faucets are open. Once the system is completely drained shut off all the faucets and turn the water back on SLOWLY. This will refreash the air on the water pipe dampers that are above the shutoff valves, if there are any, and will solve the water hammering for a while until they get saturated again.