I have a hissing noise eminating from all the waste pipes in the house which I can hear from the plug holes in the sinks and bath. The noise is loudest down stairs and quieter up stairs. Does anyone one know what's causing this please.

I have a hissing noise eminating from all the waste pipes in the house which I can hear from the plug holes in the sinks and bath. the noise is loudest down stairs and quieter up stairs. does anyone one know whats causing this please.

I don't know about your drainage but this sure sound like a small pinhole pressure leak. Assumimg that you're on city water. Turn off everything in the house and go out and check the water meter. Is the little pointer moving at all? Let me know, Tom