believe it or not it may be coming from one of
your toilets, the next time you hear it look in side your toilet tank and then
put your fingers on the rod that the ball is attached to. if the sound stops
then you need to change your fill valve. follow this link.
How to change a fill valve
Thanks. We did and the humming stopped.
We decided to replace all the guts of all the toilets in the house.
The washer were worn. After that the hum disappeared totally.
Thanks again for your help. Can't believe it was so simple to repair.
We learned the hard way, after more than $500.00 in plumbers and supplies,
all we had to do was rebuild the toilets. Thanks again. Do you need help with this project?
It may also be the Mixing
valve