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TPR Valve

Also called: T&P valve, temperature and pressure relief valve

🚿 Plumbing — a term you may see in your inspection report.

What is a TPR valve on a water heater?

TPR stands for Temperature and Pressure Relief. It's the safety valve on a water heater that opens if the tank gets too hot or the pressure climbs too high. It is one of the most important safety devices in a house, and one of the most frequently written up in inspections — usually not because the valve itself failed, but because the discharge pipe is missing, made of the wrong material, threaded on the end, terminates too high off the floor, or runs somewhere it shouldn't.

What it does
Relieves excess temperature or pressure in the tank
Most common write-up
The discharge pipe, not the valve
Typical problems
Missing pipe, wrong material, threaded end, improper termination
Why it matters
It is the last line of defense against tank failure

What it actually is

A spring-loaded valve that opens before a water heater can become a genuinely dangerous object. The discharge pipe exists to send that scalding water somewhere safe rather than at whoever is standing there.

Why it matters in East Texas

I write this up regularly, and it's almost always the discharge pipe rather than the valve. Water heaters get replaced by all kinds of people, and the discharge line is the detail that gets improvised.

What I do when I find one

I check that the valve is present and properly installed, and I examine the discharge pipe closely — material, diameter, direction of travel, termination point, and whether someone put threads or a cap on the end, which defeats the entire purpose.

What it means for you

This is usually a cheap fix and an easy negotiation item, but it's not one to ignore because it's inexpensive. It's a safety device.

More plumbing terms: Polybutylene Pipe · Cast Iron Drain Line · Galvanized Supply Pipe · Sewer Scope · Hydrostatic Test

A brass temperature and pressure relief valve on a water heater with a copper discharge line showing green corrosion staining below it
A TPR valve with its discharge line. Note the corrosion tracking down the copper below the valve — that's the valve telling you it has been letting by.
A water heater temperature and pressure relief valve with a copper discharge pipe and the original yellow warning tag still attached
Another one, with the manufacturer's tag still attached. Most of what I write up here isn't the valve — it's where the discharge pipe goes, what it's made of, and whether somebody put a cap or threads on the end.
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