Water Pouring from Pressure Relief Valve - Potential Causes and Fixes

Seeing water gushing or dripping from your water heater's pressure relief valve can be alarming. But before you panic, it's important to understand the role of this plumbing component and what different leakage scenarios indicate.

What is a Pressure Relief Valve and Why Does it Release Water?

A pressure relief valve, also called a T&P (temperature and pressure) valve, is an important safety device found on water heaters and boilers. This valve serves as a pressure 'release,' opening up to discharge water if the pressure or temperature in the tank climbs too high.

By releasing the excess heated water, the TPR valve prevents hazardous pressure buildup which could cause explosions or other dangerous situations. It's a critical fail-safe that protects the system, facility, and users.

Small amounts of water leakage from the TPR valve may occur during normal operation as pressure fluctuates. However, continuous water flow signal a problem needing attention.

Reasons Why a Pressure Relief Valve Might Leak Water

• Normal thermal expansion as the water is heated
• Pressure exceeding the valve's preset limit
• Dripping or slight weeping during heating cycles
• Failed or corroded valve disc
• Scale buildup preventing full valve closure
• Overpressurization of the system
• Improperly installed or sized valve
• Broken valve seat or worn spring

Evaluating Normal vs Abnormal Water Leakage

While a small amount of water discharge from the TPR valve is expected, larger flows or steady leakage indicate a problem. Here are signs of abnormal water loss:

• Water gushing steadily from the valve
• Constant water flow even when not heating
• Water leaking from multiple points on the valve
• Corroded or damaged valve components
• High water bills from leakage

Minor dripping or weeping during the heating cycle is generally okay. But substantial flows of water pouring from the valve require troubleshooting.

Causes of Abnormal Water Leaks

If your pressure relief valve is leaking profusely, several issues could be to blame:

• Failed valve disc - The rubber disc designed to seal the valve opening can wear out over time, causing leaks.
• Broken valve seat - Damage to the metal seat preventing full closure of the valve disc.
• Scale accumulation - Mineral deposits around the valve seat can prevent proper sealing.
• Overpressurization - Excessive pressure in the system forces the valve open.
• Improper sizing/installation - Wrong valve size or poor setup can impede function.

Pinpointing the root cause is an important first step toward resolving abnormal TPR valve leakage situations.

How to Fix a Pressure Relief Valve that Leaks Water

Repairing a leaking pressure relief valve involves a few key troubleshooting steps:

1. Inspect the Valve and Pipes

Closely examine the valve and connecting pipes for any visible damage, wear, or issues. Check for:

• Corrosion
• Cracks or leaks
• Broken/stuck components
• Obstructions
• Improper fittings

2. Clean the Valve and Remove Scale Buildup

Use a wire brush to scrub away any dirt, debris or calcium deposits around the valve seat and components. Soak parts in descaling solution or vinegar. Proper cleaning can allow the valve to seal tightly once more.

3. Adjust the Pressure Setting

If the valve is leaking from overpressurization, lowering the pressure setting 5-10 PSI below the pressure rating of the tank may solve leakage. Consult manuals for proper setting.

4. Replace Any Worn or Failed Internal Parts

Worn rubber washers, springs and valve discs may need replacing. Install replacement kits for a long-term fix.

5. Install Properly Sized Valve

If sizing is an issue, replace with a valve appropriately rated for the tank's BTU heating capacity and pressure.

In many cases, replacing the entire pressure relief valve assembly is the best solution for resolving persistent water leaks. Use caution when dismantling and replacing the valve.

How to Replace a Faulty Pressure Relief Valve

When replacing a leaking pressure relief valve, follow these steps:

1. Turn off power to the water heater at breaker box
2. Shut off the cold water inlet valve
3. Open hot water faucets to drain heater
4. Disconnect old TPR valve from pipes
5. Clean pipe exteriors and apply thread sealant
6. Install new relief valve, ensuring proper directional flow
7. Refill tank once all parts secured
8. Check for leaks and test valve response

Use proper fittings and sealants to avoid leaks. New valves should match sizing and ratings of old valve. Test after installation.

Preventing Future Leaks

To help prevent leaks from recurring, consider these tips:

• Install an expansion tank to handle thermal expansion
• Maintain water pressure within operational limits
• Remove tank sediment with annual flushing
• Test TPR valve response periodically
• Replace valve every 5-7 years or per manufacturer

Properly supporting your water heating system can maximize the lifespan of the pressure relief valve.

Know When to Call a Professional

While some minor TPR valve leaks can be managed DIY-style, it's wise to contact a professional plumber for assistance if:

• Valve replacement doesn't stop leakage
• Water damage is extensive
• The valve released due to overpressurization
• You're uncertain about the proper repair procedures

A licensed plumber has the skills, experience and tools to safely diagnose and fix persistent pressure relief valve problems.

Having water gush from the pressure relief valve can certainly be alarming and make homeowners spring into action. But not all leakage requires immediate repair. Understanding the valve's purpose along with evaluating signs of normal vs abnormal flow is important.

Minor weeping during heating cycles is expected. But substantial streams signal an issue needing attention. Most common culprits are failed internal components, overpressurization and scale buildup. Replacement or repair of the pressure relief valve will typically resolve persistent leakage issues.

A leaking TPR valve can be fixed with the right approach and precautions. Paying attention to pressure relief valve operation can save homeowners from more extensive repairs down the road.