We have an electric water heat that recently started heating the water to about boiling. We heard a loud pop one night, not sure if that has anything to do with it.

So far we just replaced the heater's thermostats thinking that was it, but after turning it back on the water was super hot again within 20 minutes.

Could it be the elements? This is in my mother's house. She is leaving soon so would rather not spend 300 on a new one since we can take back the thermostats and get elements for 100.

  • The pop was likely the temperature and pressure valve opening. Which is good, but not something you want to rely on. Very bad things happen when hot water tanks overheat if that safety valve malfunctions. (Google "mythbusters hot water heater"...or maybe don't, if you want to sleep tonight). Whatever the cause, make sure you get this fixed properly.
    – Grant
    Oct 1, 2015 at 3:43
  • 1
    Also, please add the model of the water heater.
    – Grant
    Oct 1, 2015 at 3:44

1 Answer 1


If the water heater has never been flushed and is rather old, there could be severe deposits built up inside the tank at the bottom, partly insulating the bottom sidewall where the lower thermostat is meant to sense the temperature. You might be able to compensate for this somewhat by turning down the lower thermostat to a much lower setting. "Popping" noises are common when a water heater is full of mineral deposits and corrosion from a spent sacrificial anode. Look for the UL label that shows the unit's date of manufacture. If it is 10+ years old, then it is very likely at its End of Life. It is doubtful replacing the heating elements will make much difference.

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