Why Is My Water Heater Pressure Relief Valve Leaking? Here’s What You Need to Know

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A small drip from your water heater might not seem like a big deal—but if it's coming from the pressure relief valve, it’s worth your attention.
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At Tony’s Plumbing and Heating, we get lots of winter calls about leaking water heater valves, especially when homeowners are using more hot water or heating systems are working overtime. Here’s what you should know—and when to call in the pros.

What Is the Pressure Relief Valve?
The temperature and pressure relief valve (T&P valve) is a safety feature on your water heater. It’s designed to:

• Release pressure if the water inside the tank gets too hot (usually above 210°F) or the pressure gets too high (above 150 psi)
• Prevent your tank from exploding due to dangerous pressure build-up

You’ll typically find the valve on the side or top of the water heater, with a pipe running down the side to safely direct released water.

Why Is It Leaking?
If you notice water dripping from the valve or the discharge pipe, it could mean:
1. Normal Operation

• Sometimes the valve releases small amounts of water to relieve built-up pressure—especially during high hot water usage.
• If it’s occasional and minimal, it may not be a problem.

2. Excess Pressure in the Tank

• If your water pressure is too high, the valve may open frequently.
• High pressure can be caused by:
  • A faulty expansion tank
  • High municipal water pressure
  • Thermal expansion as water heats

3. Temperature Is Too High

• If your water heater’s thermostat is set too high, it could be triggering the valve to open.

4. Faulty or Worn-Out Valve

• Over time, sediment buildup or age can cause the valve to leak constantly, even if there’s no pressure issue.
• Once the valve is compromised, it often needs to be replaced—not repaired.

Why You Shouldn’t Ignore It
A constantly leaking T&P valve is not just annoying—it’s a warning sign.
Ignoring it could lead to:

• Water damage near the heater
• Higher utility bills
• Full system failure
• In rare cases, a dangerous pressure buildup if the valve stops working entirely

What Should You Do?
Here’s what we recommend:

1. Don’t cap or plug the valve – It’s a safety feature and should always be open to release pressure if needed.
2. Check the thermostat – Make sure it’s set no higher than 120°F.
3. Look for consistent dripping – Occasional discharge is normal. Constant dripping or pooling is not.
4. Call a licensed plumber – If you're unsure whether it’s safe or if the valve needs replacing, let us take a look.

Need Help? Call Tony’s Plumbing and HeatingIf your water heater’s pressure relief valve is leaking, we can:

• Inspect and test the valve
• Check water pressure and temperature
• Replace the valve if needed
• Recommend solutions to prevent future problems (like a thermal expansion tank)

​Don’t wait for a drip to turn into damage. Call Tony’s Plumbing and Heating today—we’ll keep your hot water flowing safely all winter long.

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