Laundry room with a tank-type water heater beside the washer
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Water heater: not enough hot water / runs out fast

On electric tanks a failed lower element or lower thermostat leaves only the top of the tank hot. Other common causes on any tank are a broken dip tube, a crossed hot/cold connection in the house plumbing, reversed connections at the heater, and simple undersizing for the demand.

Cross-checked ~60 min moderateBrands: All

Before you start

  • Electric: breaker OFF and verify 0 V before touching wiring
  • Gas: no work on the gas valve or burner; diagnosis only
  • Scald risk when measuring tap temperature

Diagnostic steps

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OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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Water heater: not enough hot water / runs out fast · OnCall Tech