Name:   John boy - Subject:   Plumbing/Water Heater Question Date:   4/22/2014 5:52:38 PM

One I would replace the water heater but you will have the same problem with a new water heater unless you install an expansion tank on the cold side coming into the water heater. What happens is that you use hot water and cold water comes into tank. This happens about the time that you leave the house and the water heater heats the water which expands and with water lines having check valves. There is no place for the expansion to go but through the pop off valve. The expansion tank will stop this and an additional benefit is that when somone flushes the toilet while in the shower there is less of a change in the water volumn and temp. I had same problem is how I know and plumber explained this to me. Hope this helps.