Running water sound at hot water heater

[jm_middleton07]

If i turn on any faucet or the outside spigot I can hear a running water sound at the hot water heater. I never paid too much attention to it before because I heard the sound while someone was in the shower. We are currently filling a swimming pool with the outside spigot and it's just a constant loud running water sound. It really sounds like when the water heater is filling during use but I'm getting the sound when cold water is being used. I checked under the house for leaks and looked over the plumbing. The main water line comes into a water pressure regulator and then a check valve. From there it goes straight to the water heater and the rest of the house. I do have horrible water pressure that has gotten worse over the years. Is it possible that when the outside spigot is open it is allowing the water from the hot water heater to back flow? Should the hot water heater have it's own check valve? My house is 18 years old so it's probably time for a new water pressure regulator.

 

[arctic bill]

I would have some one with good ears listen at the tank, then turn off all water sources if the noise stops then ok no trouble , then turn off the main valve if the if the noise continues the you have a leak on your incoming line,

 

[Jeff Handy]

The pressure regulator or check valve might be going bad, restricting main water flow and also causing noise, from turbulence or that constriction.

 

[Jeff Handy]

I would service or replace the prv first.
I believe it is supposed to be checked every year anyway.

 

[Duckbutter]

Your PRV (pressure valve) should be adjustable, you can increase/decrease pressure using the bolt at the top of the "dome" shape. Though that doesn't discount the possibility it's defective.

That aside, wait until no one has used hot water for 20 minutes or so to allow the hot water line to cool, run the hose again so you can hear the sound, touch the cold & hot water lines at the water heater before and after, (it can be hot for a foot or so when not in use via heat transfer from tank), but here you want to see if hot water moves out through hot side, or the heat travels in the wrong direction on the cold feed when the hose is used.