The part(s) or condition(s) listed below for the symptom Water heater leaking are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
The temperature and pressure relief valve opens to stabilize temperature or pressure of the water heater if the temperature or pressure exceeds the proper level. The temperature and pressure relief valve opens at a set temperature. This temperature is indicated on the water heater. If the temperature and pressure relief valve leaks even though it has not reached the indicated relief temperature, replace it.
The drain valve can be opened to drain the water heater for maintenance or to flush out mineral deposits from the tank. If the drain valve is leaking, drain the tank and replace the drain valve.