What makes plumbing and drainpipes rattle all the time?
This is usually caused by the water lines not being properly secured. This can be fixed easily but only if your water lines are easily accessible. It means that there are one or more places your water lines come in contact with the wood of your floor joists. You will need to get plastic pipe hangers that go between your water lines and your joists. A defective pressure reducing valve can also cause some very strange noises. Contact a plumber for help.
