Nov 30, 2008, 08:26 AM
What is causing a hum/whistle sound early in the morning; as soon as I open up a faucet anywhere in the house the sound goes away? Two years ago I replaced the water(psi) regulator valve and gas water heater. Now, for some reason the water heater is building up pressure since the relief valve opened up this moring. Could there be a surge in water pressure coming into the house from the water company, or do I need to replace the regulator valve again?