If you’ve noticed your water heater pressure relief valve leaking, it’s natural to be concerned. This small but critical part plays a big role in protecting your water heater—and your home—from dangerous pressure buildup. At Trio Cooling, Heating & Plumbing in Cottonwood, AZ, we often get calls from homeowners asking if a leaking valve is a normal occurrence or a warning sign of something more serious. In this post, we’ll break down what this valve does, why it might be leaking, and what you should do next.

What Does the Pressure Relief Valve Do?

The pressure relief valve—also known as the T&P (temperature and pressure) relief valve—is a vital safety feature on all water heaters. It’s designed to open and release water if the temperature or pressure inside the tank gets too high. Without this valve, your water heater could become a hazard, potentially leading to tank rupture or even an explosion in extreme cases.

The valve is typically located on the top or side of your tank, connected to a discharge pipe that directs hot water safely to the floor or drain. If pressure inside the tank exceeds 150 psi or the temperature exceeds 210°F, the valve opens to release excess water and relieve stress within the system.

Common Reasons for Water Heater Pressure Relief Valve Leaking

There are several possible causes behind a water heater pressure relief valve leaking, and while some are minor, others may signal a serious issue. Let’s explore the most common reasons:

1. Excess Pressure in the Tank

One of the leading causes of valve leakage is excessive pressure. If your water heater’s thermostat is set too high, or your home’s water pressure is above the recommended range (typically 40–60 psi), it can trigger the valve to open repeatedly.

2. Thermal Expansion

When water is heated, it expands. In a closed plumbing system, where water has no place to go, this expansion raises the internal pressure. Without an expansion tank to absorb the pressure, the relief valve may open to let water out. This is common in homes with modern check valves or pressure regulators installed on the main water line.

3. A Faulty or Worn-Out Valve

Like all mechanical components, pressure relief valves can wear out over time. The internal spring mechanism may weaken, or mineral deposits can build up and prevent the valve from closing completely. In this case, even if the system pressure is normal, the valve might continue to drip.

4. Sediment or Corrosion Buildup

Hard water can lead to calcium and magnesium buildup on and around the valve. This sediment can cause the valve to stick open slightly, resulting in a continuous leak. In areas like Cottonwood, AZ, where water hardness is moderate to high, this is a common issue.

Is a Water Heater Pressure Relief Valve Leaking Dangerous?

In some cases, a leaking pressure relief valve is doing exactly what it’s supposed to—relieving excess pressure. However, if the valve leaks constantly or shows signs of corrosion, that’s not normal. Ignoring the issue could lead to:

• Increased risk of tank rupture or bursting

• Water damage to surrounding flooring or drywall

• Higher utility bills due to wasted hot water

• Mold and mildew growth from persistent moisture

Even a slow drip deserves attention. It’s best to have the system inspected by a licensed plumber to ensure the leak isn’t part of a bigger issue.

How to Inspect a Water Heater Pressure Relief Valve

You can perform a simple test to check whether your pressure relief valve is functioning properly—just be cautious. First, make sure you’re wearing gloves and safety glasses, as the water may be hot.

1. Place a bucket under the discharge pipe.

2. Gently lift the valve’s metal lever for a few seconds to allow water to flow out.

3. Release the lever and observe.

If water continues to flow after you’ve released the lever, or if no water comes out at all, the valve may be faulty and should be replaced. If you’re uncomfortable performing this test, call a professional for help.

What to Do If Your Water Heater Pressure Relief Valve Is Leaking

If you’ve confirmed your water heater pressure relief valve is leaking, take these steps:

• Check your water temperature: Ensure the thermostat is set to around 120°F.

• Measure your home’s water pressure: You can use a simple gauge on an outdoor spigot. If it’s above 60 psi, consider installing a pressure-reducing valve.

• Look for visible corrosion or buildup: This may indicate the valve is stuck open.

• Call a licensed plumber: If in doubt, it’s always better to have a professional inspect your water heater and diagnose the issue accurately.

At Trio Cooling, Heating & Plumbing, our skilled technicians offer fast, affordable diagnostics and repairs for water heaters throughout Cottonwood and the Verde Valley area.

Should You Replace the Valve?

If the valve is over 5 years old, corroded, or leaking continuously even after testing, it likely needs replacement. This is usually a straightforward job for a professional, but it involves turning off power or gas to the water heater, draining a portion of the tank, and safely removing the old valve.

However, if the root cause of the leak is high water pressure or thermal expansion, simply replacing the valve won’t solve the problem long term. Additional plumbing upgrades—like a thermal expansion tank or pressure regulator—may be necessary.

Preventing a Water Heater Pressure Relief Valve Leaking Again

Here are a few tips to help you prevent future leaks and extend the life of your water heater:

• Install a thermal expansion tank: It absorbs pressure spikes caused by water heating.

• Use a water pressure regulator: This keeps municipal water pressure at safe levels.

• Schedule annual maintenance: Have your system flushed and inspected to remove sediment and check valve function.

• Soften your water: If your water is hard, installing a softener can reduce scale buildup inside the tank.

These preventive steps can help keep your water heater in top condition while ensuring your home stays safe and dry.

Why Prompt Action Matters

Letting a water heater pressure relief valve leaking issue go unresolved can lead to serious problems—both mechanical and financial. What starts as a small drip can turn into extensive water damage or cause the tank to operate unsafely. Acting early not only protects your home but also saves you money in the long run.

Call Trio Cooling, Heating & Plumbing Today

If you’re dealing with a water heater pressure relief valve leaking, don’t wait for it to get worse. At Trio Cooling, Heating & Plumbing, we’ve helped hundreds of homeowners in Cottonwood, AZ and nearby areas resolve water heater issues quickly and professionally. Whether you need a simple valve replacement or a full system evaluation, our expert team is here to help.

Call us today or book an appointment online to get peace of mind and professional service you can trust.