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How to fix a pressure relief valve leak

We'll confirm the leak location, test the valve, replace it if faulty, and check system pressure—or tell you when to call a plumber.

Troubleshooting · Home plumbing
30–60 min
What you'll need
  • Pipe wrench
  • Replacement pressure relief valve (match pressure and temperature rating)
  • Pipe thread sealant (Teflon tape or dope)
  • Garden hose and bucket (for draining)
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Steps

Goal: Confirm the leak location, shut off power and water, test the valve, and replace it if faulty.

  • Dry the area around the water heater. Confirm water comes from the pressure relief valve or its discharge pipe—not from the tank, drain valve, or connections.
  • Good: Leak at valve or pipe. Proceed to Shut off power and water.
  • Bad: Tank is wet or rusty—call a plumber. The tank cannot be repaired.

Confirm leak location

Goal: Verify the leak is at the T&P valve, not elsewhere.

  • The pressure relief valve sits on the top or side of the tank with a discharge pipe running down. Check that water emerges from the valve body or the pipe.
  • If the tank itself shows wet spots, rust, or corrosion, do not proceed—call a plumber.
  • Good: Leak at valve or pipe. Proceed to Test the valve.
  • Bad: Tank leaking—see When to get help.

Shut off power and water

Goal: Make the water heater safe to work on.

  • For electric: turn off the circuit breaker. For gas: turn the gas valve to pilot or off. Shut off the cold water supply valve above the tank.
  • Open a hot water faucet to relieve pressure until water stops.
  • Good: No power or gas and no water flow. Proceed to Test the valve.
  • Bad: Power, gas, or water still on—find the correct shutoffs.

Test the valve

Goal: Determine if the valve is faulty or weeping from high pressure.

  • Lift the lever on the pressure relief valve briefly. Water should discharge from the discharge pipe, then stop when you release the lever.
  • If water continues to drip after you release, the valve seat is worn—replace the valve.
  • If no water comes out when you lift, the valve or pipe may be blocked—call a plumber.
  • Good: Drip stops after release—check the discharge pipe and system pressure. Bad: Drip continues—proceed to Replace the valve.

Check the discharge pipe

Goal: Confirm the discharge pipe is not blocked.

  • The discharge pipe must run down to within 6 inches of the floor with no caps or obstructions.
  • Clear any debris from the pipe opening. A blocked pipe can cause pressure to force the valve to weep.
  • Good: Pipe is clear. If the valve still weeps, check system pressure. Bad: Pipe is blocked or inaccessible—call a plumber.

Replace the valve

Goal: Install a new pressure relief valve when the old one is faulty.

  • Attach a hose to the drain valve and drain a few gallons to lower the water level below the T&P valve.
  • Unscrew the old valve with a pipe wrench (counterclockwise). Note the pressure and temperature ratings (typically 150 psi, 210°F).
  • Buy an exact match. Wrap the new valve threads with pipe thread sealant. Screw it in clockwise until hand-tight, then snug a quarter turn with the wrench—do not overtighten.
  • Close the drain valve, remove the hose, turn the water supply back on. Open a hot faucet to bleed air. Restore power or gas.
  • Good: No drips at the valve or pipe after 30–60 minutes. Proceed to Verification.
  • Bad: Still drips—check system pressure or see When to get help.

Check system pressure

Goal: Rule out high pressure as the cause of weeping.

  • Attach a pressure gauge to a hose bib or laundry connection. Typical target is 50–60 psi.
  • If pressure exceeds 80 psi or fluctuates, you may need an expansion tank or PRV adjustment—call a plumber.
  • Good: Pressure is in range. The valve may have been temporarily weeping; monitor. Bad: Pressure is high—call a plumber.

When to get help

Call a plumber if:

  • The tank itself is leaking (wet spots, rust on the tank).
  • The valve still drips after replacement.
  • You need an expansion tank installed.
  • System pressure stays high.
  • You have a gas water heater and are not comfortable.
  • The discharge pipe is inaccessible.

If you smell gas, evacuate immediately. Do not turn on lights or appliances. Call 911 or your gas utility from outside.

Verification

  • No water drips from the pressure relief valve or its discharge pipe when the tank is at normal temperature and pressure.
  • The valve passes the lever test—brief discharge when lifted, then stops when released.
  • System pressure (if checked) is in the safe range (50–60 psi ideal).
  • No leaks at the valve threads or pipe connections after 24 hours.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm leak location Verify the leak is at the T&P valve or discharge pipe, not the tank.
  2. Check discharge pipe Confirm the pipe is not blocked.
  3. Test the valve Lift the lever briefly; if it drips after release, replace the valve.
  4. Replace the valve Drain a few gallons, unscrew the old valve, install an exact match.
  5. Check system pressure If the valve still weeps, check pressure; expansion tank or PRV may be needed.
  6. Call a plumber Tank leaking, valve still drips after replacement, expansion tank needed, or not comfortable.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Leak location (valve, pipe, tank)
  • Valve test result (drips after lever release?)
  • Valve pressure and temperature rating
  • System pressure reading (if checked)
  • Steps already tried

Is the leak at the pressure relief valve or its discharge pipe?

The T&P valve sits on the top or side of the tank with a pipe running down. The tank itself, drain valve, and connections are different.

Dry the area. Check that water comes from the pressure relief valve or its discharge pipe—not from the tank surface, drain valve, or inlet/outlet. Good: leak at valve or pipe. Bad: tank is wet or rusty—call a plumber; the tank cannot be repaired.

Yes No (tank leaking)

You can change your answer later.

Does the valve stop dripping when you release the lever?

Lift the lever briefly. Water should discharge, then stop when you release. Constant drip after release means a faulty valve.

Shut off power and water first. Lift the lever on the pressure relief valve briefly. Water should discharge from the pipe, then stop when you release. Good: drip stops—valve may be weeping from high pressure; check discharge pipe and system pressure. Bad: drip continues after release—valve is faulty; replace it.

Yes (stops) No (continues)

You can change your answer later.

Is the discharge pipe blocked?

The pipe must run down to near the floor with no caps. A blocked pipe can cause pressure to force the valve to weep.

Check the discharge pipe. It must run down to within 6 inches of the floor with no caps or obstructions. Clear any debris. Good: pipe is clear—check system pressure; high pressure may need an expansion tank or PRV adjustment. Bad: pipe is blocked or inaccessible—call a plumber.

No (clear) Yes (blocked)

You can change your answer later.

Clear the pipe and retest

Clear debris from the discharge pipe. Retest the valve. If it still weeps, check system pressure or replace the valve.

Done

Is system pressure too high?

Attach a gauge to a hose bib. Typical target is 50–60 psi. Over 80 psi can cause the valve to weep.

Attach a pressure gauge to a hose bib or laundry connection. Turn water on. If pressure is over 80 psi or fluctuates, you may need an expansion tank or PRV adjustment. Good: pressure is 50–60 psi—valve may have been temporarily weeping; monitor. Bad: pressure is high—call a plumber for expansion tank or PRV work.

Yes No

You can change your answer later.

Replace the pressure relief valve

Drain a few gallons, unscrew the old valve, install an exact match for pressure and temperature rating.

Drain a few gallons from the tank. Unscrew the old valve with a pipe wrench. Buy an exact match (same pressure and temperature rating). Apply pipe thread sealant, screw in the new valve, snug with wrench. Refill the tank and restore power or gas. Good: no drips after replacement. Bad: still drips—check system pressure or call a plumber.

Fixed Still drips

You can change your answer later.

Leak is resolved

The valve no longer drips. Monitor for a few days. If it weeps again, check system pressure or call a plumber.

Done

Call a plumber

Call a plumber if: the tank is leaking, the valve still drips after replacement, you need an expansion tank or PRV work, or you have a gas water heater and are not comfortable. If you smell gas, evacuate and call 911 or your gas utility from outside.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why does my pressure relief valve leak?
Common causes: a worn or faulty valve seat, high system pressure (no expansion tank or failed PRV), or a blocked discharge pipe. The valve releases when pressure or temperature exceeds safe limits—if it drips constantly, the valve or system pressure needs attention.
Can I replace a pressure relief valve myself?
Yes, if you shut off power, gas, and water first. Drain a few gallons from the tank to relieve pressure. Unscrew the old valve and install a new one with the same pressure rating (typically 150 psi) and temperature rating. Use pipe thread sealant. If you have a gas water heater and are not comfortable, call a plumber.
When should I call a plumber for a pressure relief valve leak?
Call a plumber if: the tank itself is leaking, the valve still drips after replacement, you need an expansion tank installed, you have a gas water heater and are not comfortable, or system pressure stays high after checks.

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