Possible Duplicate:
How to eliminate the “whooshing” sound of water running though pipes.
I have a 3 story townhouse. Any time when I open a tap, even very slowly that water is just dripping, it makes a hissing (can't really explain it, its kind of like hissing, sssssss) noise that can be heard on all levels. If someone opens the tap in the basement, I can hear it in my third level master bedroom and is a problem at night when the noise can wake me up.
Any idea what might be causing this?
