Gas Water Heater Question

We have a 50 gal gas water heater (app. 5 years old). For the past few months have noticed sizeable increase in water usage. Several days ago noticed what sounds like water constantly running thru the overflow pipe (running from the TP valve). The pipe is very warm to the touch and feels like water running thru pipe. No leaking in house or below foundation that is obvious. Would this be caused by a faulty TP valve or something more serious?

It could be a leaking T&P but it could be something more serious. Is the burner running continuously or does it shut down normally? Have you checked the water pressure? Is there a PRV valve on the system and is there an expansion tank? Basically the folks here will need a complete description of the system and it's operation. Then they will still tell you to get it checked by a plumber which isn't a bad ideal if you don't deal with this stuff every day.

Yes, it is probably the T&P valve leaking. When did you last test it? Can you see the end of the drain piping from the T&P valve?

Go to the nearest "big box" store and buy an new T&P valve along with some teflon tape if you do not already have some. This is because you may need to replace the valve after testing it. A new valve costs less than $10.

Assuming that the open end of the drain piping is in an area where a large flow of water will cause no harm, pull the handle on the T&P valve smartly to the full open position, let it blow a couple of seconds and then release it. If your drain pipe is located where a flow will cause damage then it needs to be relocated. For now you can put a five gallon bucket under it.

Wait for about ten minutes and see if the drain line is still dripping. If not you are okay. If it is dripping then wait another hour and check again. If it is still dripping then you need to replace the T&P valve.

The TP valve is the likely culprit. These are easy to change and are available at any hardware store or plumbing shop. Turn the water supply off, release the pressure and drain the tank down a tad by opening a hot water faucet. Remove the overflow pipe from the TP, then remove the TP. This will require a fairly stout pipe wrench. Use either Teflon tape or pipe dope on the threads of the new TP and install it in the tank. Replace the overflow pipe, and restore the water supply.

check your water pressure and the temperature of the hot water. that is your first step.