Water Heaters

T&P relief valve dripping or discharging

The T&P valve is the tank's last line of defense. It may be failing, or it may be doing its job because the house pressure is too high or thermal expansion has nowhere to go (check valve or PRV on the supply). Diagnose with a pressure gauge; replacement of the valve itself is licensed plumber work in many jurisdictions. Never cap or plug it.

Cross-checked ~45 min moderateBrands: All

Before you start

  • Never plug, cap or reduce the T&P discharge; doing so can turn the tank into an explosion hazard
  • Discharge water can be scalding
  • If the valve is releasing very hot water/steam, cut energy to the heater (breaker OFF or gas control OFF) and refer immediately
  • T&P valve replacement and expansion-tank/PRV work: licensed plumber where required by local code

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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T&P relief valve dripping or discharging · OnCall Tech