For several weeks, we've noticed intermittent humming sounds with occasional pulsing, loudest in the bathrooms. Shutting off the electricity made no difference. Early this morning the noise was particularly loud. I opened and shut a bathroom basin valve, then heard definite pulsing, from silent to loud, that subsided to a hum after a few seconds--so it's definitely a plumbing problem. Two hours later, I heard nothing. Checked the toilet overflow valves; the tops are a half inch above the water level. When there's humming in the bathroom, there doesn't seem to be a noise from the water heater and there's no vibration in the hot water line running from the heater. I'm out of ideas! Any suggestions would be much appreciated.

It could be from a loose washer on one of you angle valves either from the toilet or sink angle valves, to find out I would close the toilet angle valve first, flush the toilet wait and see if the noise still exist if no noise it means it is the toilet angle valve or the ballcock.

If the noise is still there than the problem is with sink valves, once you check as above get back to us, Thanks.

John

Further info about this problem: As suggested in an answer to a similar question, I shut off the cold water valve to the water heater--no effect on the hum. There seemed to be no vibration in the hot water line leading from the heater. The pulsing sound in the hum occurred when I turned on (and then off) either the hot or the cold water in either of the bathroom hand basins. Similarly when either toilet was flushed. However, when I turned on the cold water (but not the hot water) in the bath tub in the bathroom where the hum is loudest, there was little or no pulsing and the hum seemed to subside or stop, at least temporarily. This does seem to be a vibration problem, but where? And how can I fix it?

It sounds like the problem is with the ball cock, the noise you hear is the washer vibrating against the seat as the tank fills. The solution would be to S/O the water at the angle stop, remove the tank lid and remove the three screws on top of the ballcock pull the float ball and stem and washer assembly up and out, Pry the washer out with a flat screw driver and turn it over. With the ballcock still open, slightly turn on the water to flush the supply out. Check the linkage between the flapper and the flush lever. It should have ¼” to ½”of play when your tank is full.
(Loose washer at end of angle vale stem will also make the noise)

Can you tell us which type of ballCock is installed in your toilet tank see the pictures, Thanks.

John