Why Is My Water Heater Leaking?

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Why Is My Water Heater Leaking?

It’s hard not to be grateful for a working water heater. But what happens when you find your hot water heater leaking? A lot of questions may come to mind and City Base Plumbing is here to help!

Key Takeaways:

  • Several factors can cause your water heater to leak, including issues with the pressure relief valve, drain valve, or a cracked storage tank.
  • Regular water heater maintenance can help find problems early and prevent extensive damage.

What Causes Water Heater Leak?

Water heaters are among the most reliable appliances in our homes but they can have problems. Let’s look at the main causes we have run into at City Base Plumbing:

Pressure Relief Valve (P Valve)

The pressure relief valve, also referred to as the temperature and pressure relief (T&P) valve, plays a big role in maintaining the safe operation of water heaters. Its main function is to reduce naturally occurring water pressure within the tank, especially when the temperature rises too high. Here’s a more detailed breakdown:

  • Functionality: As the water inside the heater warms up, it expands, leading to an increase in pressure. When this pressure surpasses the valve’s set limit, it releases water as a safety measure. This is so the water heater tank doesn’t face extreme pressure, which can be dangerous.
  • Potential Problems: A malfunctioning P valve, or one that’s clogged with sediment, might not release pressure as it should, leading to potential leaks. If inbound water pressure from the water supply is too high, it can put excessive force on the valve.
  • Solution: Regularly inspect the P valve to check if it operates correctly. If you suspect a malfunction or notice your water heater leaking from the P valve, consider replacing it. It’s also a good idea to monitor your water temperature, checking for excessively hot water which can generate unnecessary pressure.

Drain Valve

A problematic drain valve at the bottom of a water heater.

The drain valve is located near the bottom of the water heater tank and is used for routine maintenance and draining sediment:

  • Potential Problems: The drain valve may become loose or develop a fault. Either the drain valve isn’t correctly sealed, or it might get damaged due to wear and tear which causes a leak.
  • Solution: Regularly inspect the drain valve for signs of leakage. Tighten it if it appears loose but avoid over-tightening. If the valve is faulty, replacing it with a new drain valve is typically the best solution.

Cracked Storage Tank

The storage tank plays a big role in tank-based water heaters:

  • Causes: Natural minerals in the water, like calcium and magnesium, can settle at the bottom of the tank. These sediments heat and reheat, leading to potential cracks in the tank’s internal shell. Corrosive elements in the water can also degrade the tank lining over time.
  • Signs: If you see water pooling around the base of your water heater or notice moisture between the internal and external shells, this is a sign of a compromised internal tank.
  • Solution: Sadly, a cracked storage tank usually means you’ll need an entirely new water heater.

Inlet and Outlet Connections

These are the points where cold water enters the tank, and hot water exits:

  • Potential Problems: These connections can loosen, leading to water leaks. Corrosion or faulty installation can also hurt these connections.
  • Solution: Regularly inspect the cold water inlet pipe and the hot water outlet connection. If you identify any drips or signs of leakage, tighten the connections using a pipe wrench. Don’t over-tighten, which could damage the threads or connections.

Anode Rod and Water Quality

A old Anode Rod that needs to be replaced.

The anode rod is made of magnesium or aluminum designed to protect the internal tank:

  • Functionality: It attracts corrosive elements in the water, which prevents the tank from rusting. Over time, the anode rod corrodes and becomes less effective.
  • Impact of Water Quality: High mineral content, especially calcium and magnesium, can accelerate the deterioration of the anode rod. Poor water quality can also directly impact the longevity of the water tank.
  • Solution: Regularly inspect and replace the anode rod if it’s heavily corroded. If you live in an area with hard water, consider using a water softener to improve water quality and extend the life of your water heater and its components.

Checking For Water Heater Leaks

Regular Checks and Maintenance By inspecting your water heater frequently and scheduling preventative maintenance, you can detect potential issues before they become significant problems. This includes checking the temperature and pressure relief systems, the condition of the anode rod, and checking for active leaks.

Professional Plumber Consultation If you’ve examined the usual suspects like the drain valve, the inlet and outlet connections, or the P valve and still can’t identify the leak’s source, it’s time to reach out to a professional plumber. We have the tools and expertise to check the entire plumbing system, including the gas line for gas water heaters or the dedicated shutoff valve for electric water heaters.

Water Heater Replacement In situations where the water tank has been compromised, or the heater is old and beyond repair, consider a water heater replacement. Modern water heaters can be more energy-efficient and provide better water quality, which can be beneficial in the long run.


Water heater leaks occur for different reasons, from simple issues like a loose drain valve to more severe problems like a cracked internal shell. Regular water heater maintenance and being proactive can help you address these concerns. Always remember, when in doubt, consult with a professional plumber for complete peace of mind.

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