My roommates and I have been hearing a knocking sound in our pipes at different times of day or night. We have not had any work done on the pipes and wondering what could be the problem. I don't think we even used the water at times when there was knocking. Any ideas would be helpful---thanks Keri

Close the angle valve under your toilet tank flush the toilet, leave it overnight and see if you still hear that noise if not the problem is with your toilet fill valve or loose washer in your angle valve, if the noise is still there then we can proceed further trouble shooting, Thanks.

John