our hot water heater is making a noise that sounds like hissing or maybe steam being released. I pulled the fuse and the noise continues. I have drained about 1/2 gallon from the heater and no change. I have turned off the inflow and no change. There is no leak noticeable and no signs that the pressure relief valve is leaking. Any ideas??
I assume you have a house with a concrete floor and copper underneath it. You have a leak in the tubing somewhere. Normally it is the hot water, but if the noise continues after the water control valve is turned off, (and no water will come out of a hot water faucet when it is opened), then it is one of the rare cold water leaks. About the only way to locate it is to hire a leak locator service. Then a plumber to fix it. Also contact your home owner’s insurance company, since this is usually covered by your policy.