Pipe wrench
Use it for: To loosen and tighten the old and new valve without rounding it off.
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How to Replace a Water Heater Temperature Pressure Relief Valve
To replace a water heater temperature pressure relief valve, shut off power or gas, close the cold water supply, relieve tank pressure, remove the old valve, install the matching new valve, reconnect the discharge tube, and test for leaks during a full heat cycle.
This repair is usually the right move when the relief valve body is leaking, the valve keeps dripping after testing, or it will not reseat properly. If the valve is opening because the tank is overheating or pressure is too high, replacing the valve alone will not solve the root problem.
Before you start: Match the valve size, pressure and temperature rating, probe length if applicable, and the connection style used on your water heater before ordering.
Safety first
- Let the water cool before working if the heater has been running recently.
- Shut off power to an electric heater or turn off a gas heater before draining or opening the tank.
- Do not cap, plug, or block the relief valve discharge tube.
- Restore power or gas only after the tank is completely full of water.
Tools you may need
Adjustable wrench
Use it for: To hold fittings or remove the discharge tube if needed.
Shop adjustable wrenches
Bucket
Use it for: To catch water when you relieve pressure and remove the valve.
Shop buckets
Garden hose
Use it for: To drain a little water from the tank to lower the water level below the valve opening.
Shop garden hoses
Thread sealant or PTFE tape
Use it for: To seal the new valve threads if your valve uses threaded connections.
Shop thread sealant
Work gloves
Use it for: To protect your hands from hot fittings and sharp edges.
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Step-by-step fix
Step 1: Confirm the relief valve is the problem
- Look for water coming from the relief valve body, around its threads, or from the discharge pipe attached to it.
- Check whether the leak happens even when the test lever is fully closed and untouched.
- Make sure the water heater is not obviously overheating, making boiling sounds, or producing dangerously hot water at faucets.
- Inspect the area around the valve opening and tank shell for rust swelling, cracks, or signs the tank itself is failing.
If it works: You have confirmed the leak or failure is centered at the temperature pressure relief valve and not from a nearby fitting or a failing tank.
If it doesn’t: Dry the area, run the heater normally, and trace fresh water carefully. If the leak starts above the valve or from the tank seam, this is not the right repair.
Stop if:
- The tank shell is leaking, split, badly rusted, or bulging.
- Water at fixtures is scalding hot or the heater shows signs of overheating.
- The discharge pipe is missing, capped, or installed in an unsafe way you are not prepared to correct.
Step 2: Shut the heater down and relieve pressure
- Turn off electrical power at the breaker for an electric water heater, or set a gas unit to off and follow the normal shutdown control on the heater.
- Close the cold water supply valve feeding the tank.
- Open a nearby hot water faucet to relieve pressure in the system.
- Place a bucket under the relief valve area.
- Attach a garden hose to the drain valve and drain a little water from the tank so the water level drops below the relief valve opening.
If it works: The heater is off, incoming water is shut off, pressure is relieved, and the water level is low enough to remove the valve without a full spill.
If it doesn’t: If water keeps flowing strongly with the supply valve closed, the shutoff valve may not be closing fully. You may need to shut water off farther upstream before continuing.
Stop if:
- The water is still too hot to work around safely.
- The shutoff valve or drain valve is damaged and cannot be operated safely.
Step 3: Remove the old valve and discharge tube
- If the discharge tube is threaded into the relief valve, loosen and remove that tube first.
- Support nearby piping as needed so you do not twist or crack connected fittings.
- Use a pipe wrench on the relief valve and turn it counterclockwise to remove it from the tank opening.
- Keep the bucket in place because some remaining water may spill as the valve comes out.
- Inspect the tank threads and opening for mineral buildup, old sealant, or damage, and clean the threads enough for the new valve to seat properly.
If it works: The old relief valve is out, the discharge tube is disconnected, and the tank opening is clean and ready for the new part.
If it doesn’t: If the valve is badly seized, apply steady pressure and reposition the wrench for better leverage. Avoid jerking hard enough to damage the tank fitting.
Stop if:
- The tank threads are cracked, stripped, or too damaged to hold a new valve securely.
- Removing the valve causes the tank fitting to move or deform.
Step 4: Install the new relief valve
- Compare the new valve to the old one to confirm the same size and connection style.
- Apply thread sealant or PTFE tape if the valve uses threaded male pipe threads.
- Thread the new relief valve into the tank by hand first to avoid cross-threading.
- Tighten it with a pipe wrench until it is snug and oriented so the discharge connection points downward in a workable position.
- Do not overtighten to the point that you risk damaging the tank fitting.
If it works: The new relief valve is installed squarely, tightened securely, and positioned for the discharge tube connection.
If it doesn’t: If the valve will not thread in smoothly by hand, back it out and start again. Cross-threading will ruin the connection.
Stop if:
- The new valve does not match the old valve's size or connection type.
- The valve cannot be tightened without binding, cross-threading, or damaging the tank opening.
Step 5: Reconnect the discharge tube and refill the tank
- Reconnect the discharge tube to the new relief valve.
- Make sure the tube points downward and is not capped or blocked.
- Close the tank drain valve and remove the hose.
- Open the cold water supply valve to refill the tank.
- Leave a nearby hot water faucet open until air stops sputtering and a steady stream of water flows, then close the faucet.
- Restore power or gas only after the tank is completely full.
If it works: The tank is full, the discharge tube is reconnected, and the heater is ready to return to service.
If it doesn’t: If the tank will not fill normally, recheck that the drain valve is closed and the cold water supply is fully open.
Stop if:
- The discharge tube cannot be reconnected securely.
- You find a blockage, cap, or other unsafe condition on the discharge path.
Step 6: Check for leaks and confirm the repair holds
- Dry the valve, tank opening, and discharge tube connection with a towel.
- Watch closely for seepage around the valve threads and the discharge tube connection as the tank refills.
- After the heater returns to normal temperature, check again for dripping from the discharge pipe or around the valve body.
- Run hot water at a faucet for a few minutes, then let the heater recover and inspect the valve one more time.
- If the valve stays dry through refill and a full heating cycle, the repair is holding.
If it works: The new relief valve stays dry in real use, and there is no unwanted dripping from the discharge pipe after the heater reheats.
If it doesn’t: If the new valve still drips, the root cause may be excess temperature or pressure in the system rather than a bad valve. The heater needs further diagnosis before parts are changed again.
Stop if:
- The new valve leaks immediately from damaged threads or a cracked connection.
- The valve opens repeatedly after replacement, suggesting an overheating or overpressure problem.
- You smell gas, see electrical issues, or notice the tank itself beginning to leak.
Replacement Parts
Find a water heater temperature pressure relief valve on Amazon
Match the valve size, pressure and temperature rating, probe length if applicable, and the connection style used on your water heater before ordering.
As an Amazon Associate I earn from qualifying purchases. Repair Riot may earn a commission at no extra cost to you.
Verify the repair
- No water seeps from the valve threads or discharge tube connection during refill.
- No dripping comes from the discharge pipe after the heater completes a normal heating cycle.
- Hot water service returns normally without scalding temperatures or unusual boiling sounds.
- The area around the top or side of the tank stays dry over the next day of normal use.
FAQ
Why is my water heater relief valve dripping?
A relief valve can drip because the valve itself is worn or fouled with mineral buildup, but it can also open for a reason. Excess tank temperature, excess system pressure, or a control problem can make a good valve release water.
Can I replace a relief valve without draining the whole water heater?
Usually yes. You normally only need to shut off the supply, relieve pressure, and drain enough water to bring the level below the valve opening.
Do I need thread tape or pipe sealant on the new valve?
If the replacement uses threaded pipe connections, thread sealant is commonly used. Apply it to the valve threads only, and do not get sealant inside the valve opening.
What if the new relief valve still leaks after replacement?
That usually points to a pressure or temperature problem rather than a bad new valve. The heater may be overheating, or the plumbing system may be seeing excess pressure.
Can I reuse the old discharge tube?
You often can if it is the correct type, undamaged, and reconnects securely to the new valve. Do not reuse it if it is corroded, blocked, cracked, or does not fit the new valve properly.