Plumbing Review - Noisy Water Pipes

Q : Since we've been on higher water pressure from a new source, we are getting more noise in the pipes. Not banging or clunking, just more water moving through the system quicker, sort of a "rushing" noise. The pipe into the house is plastic, then hooks into copper pipe. The noise reverberates down the entire line, and since the pipe is strapped to the floor rafters, it makes the noise under the kitchen, toilet and one bedroom. I know about having a foot or so of capped pipe going up from a line to trap air and soften the noise of "on" and "off" clunking, but this has me stumped. I am at the point now where I am about prepared to rip the strapping off and putting foam around the pipes before I strap them back up. Before I spend the cash on this, I thought I would check with you to work out if that's what I need to do, or are you suggest something else ? Thanks extraordinarily much.

A : A reduction of 1.5:1 ( often 3/4" to 1/2" is commonly used to increase or maintain water pressure thru a house. The concept is that, given consistent supply pressure, proscribing volume will increase speed. Released pressure at a fixture will be compensated for by this increased velocity.

I expect your hot and cold supply pipes are 1/2 inch diameter. What diameter is the plastic feed? If the reduction is greater than 1.5:1 it's quite likely that the velocity is great sufficient to cause noise in the pipe.

Check that all the shut-off valves (below the sinks for example. ) are absolutely open. They also, could cause turbulence/noise by restricting water flow. Also, check all the pipes to work out if there are any crushed or dented sections.

Foam wrap is a superb for insulating purposes, but maybe a little too soft for noise damping ( it might crush flat). By all means, wrap the pipes, but use denser rubber for vibration pads. Extra bracing (for clamping to) might also help.

Alternative: Before you start pulling out nails, check the water velocity at your fixtures, and if it is extremely high, a pressure reducing valve can be installed on the supply line.