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Plumbing Glossary

T&P Relief Valve

A safety valve on tank water heaters that opens if temperature or pressure exceeds safe limits. Discharge pipe must route to a visible floor drain or exterior.

T&P Relief Valve

Also called: Temperature and Pressure Relief Valve, T&P Valve

What it means

The T and P relief valve monitors water heater tank conditions. If the thermostat fails or pressure spikes, the valve opens to release hot water and prevent tank rupture.

Discharge piping must be rigid or semi-rigid copper or CPVC, terminate near the floor, and never be capped. Dripping valves may indicate expansion tank issues, excessive pressure, or a failing valve.

Why it matters in Santa Cruz County

Garage and closet water heaters common in Santa Cruz County must have properly routed T and P discharge to avoid scalding hazards near stored goods. Missing expansion tanks on closed systems cause nuisance dripping during heating cycles.

Homeowner tip

Never cap or plug the pipe from the T and P valve; call a plumber if it drips more than occasionally.

Related Wade's services

Also explore the Septic Glossary or call 831.225.4344 with questions about your property.