Pipes Groan

Hi,

Whenever I flush the toilet I hear the pipes in the basement groan and once it stops fills up with water it groans again. When I turn off the water of the shutoff valve in the toilet and flush it doesn't make any noise. Also, I can hear it when I turn on the washing machine. and when it flushes out the water it makes that groaning noise again. Does anyone know what is the problem and how to fix it. Thanks in advance!

Lis

It could be either a bad fill valve in the toilet,

or,

A pressure reducing valve (PRV) in the basement making the noise.

Do you have one of these on you main water supply pipe in the basement, it is usually near the water meter?