Water Heater Leaking: Causes and Quick Fixes


// Posted by Eco Heating & Air Solutions, Inc.

When your water heater starts leaking, it can be a big hassle and might cost a lot. Knowing why your water heater leaks and acting fast can fix the issue and stop more damage. We'll look at why your water heater might leak and give you ways to fix it.

Key Takeaways

  • The most common cause of water heater leaking is a damaged or failing pressure relief valve.
  • Potential causes of water heater leaking include a cracked or corroded water heater tank, loose or faulty fittings and pipe connections, and a worn-out anode rod.
  • Regular maintenance, such as flushing the tank and checking the pressure relief valve, can prevent costly repairs and leaks.
  • Investing in a new, energy-efficient water heater can lead to long-term savings on energy bills and improved safety features.
  • Addressing water heater leaks promptly can help prevent further damage and costly repairs.

Common Causes of Water Heater Leaks

A leaking water heater can be frustrating and costly. Knowing the common causes can help you fix the issue quickly. Factors like an old water tank, drain valve problems, and high internal pressure can lead to leaks.

Old Water Tank

An aging water tank is a top reason for leaks. As tanks get older, parts can break down, causing rust and corrosion. This can lead to cracks or holes, letting water leak out. It's important to check and replace old tanks to avoid these problems.

Drain Valve Issues

The drain valve at the water heater's bottom can leak too. Over time, it might not be tight or could crack, causing leaks. Keeping the valve tight and working right is key to stop leaks.

High Internal Pressure

High pressure inside the water heater can cause leaks. This pressure might come from a faulty valve, sediment, or blocked water flow. When pressure gets too high, it can push water through any cracks, causing leaks.

Malfunctioning Temperature and Pressure Relief Valve

The temperature and pressure (T&P) relief valve is key to your water heater's safety. It lets steam and hot water out when the pressure inside gets too high. But, if it breaks, it might start leaking.

Debris or sediment can make the valve not work right or not close fully, causing leaks. Setting the water heater's temperature between 120-125 degrees Fahrenheit helps avoid the valve opening too much. An expansion tank can also manage extra pressure, stopping leaks.

Regular checks and maintenance can stop sediment buildup and leaks. Corrosion from metal parts can weaken the valve area, leading to leaks too.

A broken valve can make the water heater explode, which is a big risk. Checking the pressure gauge should be between 40 psi - 80 psi. If the water gets too hot, it can also make the valve leak.

Fixing a broken valve is not expensive, costing about $30. Regular checks and flushing the water heater monthly can stop leaks. It's smart to have a pro check the system yearly to find problems early.

Inlet and Outlet Connection Problems

Water heater leaks often come from issues with the cold water inlet and hot water outlet connections. These connections can get loose over time, letting water drip out. Faulty or damaged fittings can also cause leaks.

Loose or Faulty Connections

The connections on your water heater can loosen due to constant pressure and vibration. This may cause small leaks. If they weren't tightened right when installed or have worn out, they might not seal well anymore, leading to leaks.

Dielectric Union Requirements

Sometimes, a dielectric union is needed to connect the water heater's pipes to your plumbing. This union stops corrosion between different metals, preventing leaks. Not using a dielectric union or installing it wrong can lead to leaks.

Fixing inlet and outlet connection problems is key to stopping water heater leaks. Check these fittings often and make sure they're tight. This can prevent future leaks and water damage.

Leaks from the Temperature and Pressure (T&P) Valve

Leaks often come from the temperature and pressure (T&P) valve. This valve is a safety feature that releases pressure or temperature to stop the water heater from exploding. But, if it's not installed right or if the heater gets too hot or pressurized, leaks can happen.

Improper Installation or Sealing

Leaks can happen at the T&P valve if it wasn't set up correctly. This might be because the valve wasn't tightened enough or the gasket didn't fit right. If the valve isn't sealed well, water can leak out.

Excessive Water Heating or Pressure

Too much heat or pressure in the water heater can make the T&P valve open and leak. This could be from a broken thermostat or a faulty heating element. High pressure in the plumbing can also make the valve leak, even if the water isn't too hot.

Our research shows many people were looking for help with leaking T&P valves on our blog. Replacing a T&P valve costs less than $15, which is a small price to pay. But, fixing the real cause of the leak, like bad installation, too much heat, or high pressure, is key to stopping it from happening again.

Drain Valve Leaks

Drain valves at the bottom of water heaters often leak due to becoming loose, corroded, or damaged over time. These valves are a common source of leaks. It's important to check them regularly.

Plastic drain valves can get brittle and leak as they age. The rubber gaskets inside can also wear out, causing leaks. Sediment inside the valve can lead to leaks too.

If you see water pooling under your water heater or a slow drip from the drain valve, it's leaking. Sometimes, you might hear hissing sounds from the valve, which means there's a problem.

Fixing a Leaking Drain Valve

To fix a leaking drain valve, you'll need some tools and equipment:

  • Pliers, an adjustable wrench, or a pipe wrench
  • Teflon tape
  • A bucket or hose for water drainage
  • A replacement valve (if necessary)

First, turn off the water and power to the water heater. Then, drain the tank by attaching a hose to the drain valve and opening it. After draining, replace or repair the valve as the manufacturer directs. If it's too corroded or damaged, get a new one.

Always wear protective gloves and safety goggles when working on your water heater. This protects you from scalding and water damage. If you're not sure how to fix it, call a professional plumber.

water heater leaking from the Tank

When your water heater tank gets a big crack or bursts, it can leak a lot. This leak is often from sediment and corrosion building up over time.

Major Tank Rupture

A full tank rupture is a big problem with water heater leaks. It usually happens because the tank is old, not maintained well, or has too much pressure. Once it cracks or bursts, water will flow out fast, causing a lot of damage to your home.

Sediment Buildup and Corrosion

Sediment and mineral deposits can gather at the tank's bottom over time. This can cause corrosion, making the tank weak and more likely to leak. Not cleaning your water heater often makes this worse, making it more prone to leaks and failure.

If you see your water heater tank leaking, you should fix it quickly to stop more damage. Call a skilled plumber to find out why it's leaking and what to do next. They might suggest fixing it or replacing the water heater.

Other Potential Leak Sources

Water heater leaks can come from places you might not expect. Besides the usual causes like a faulty valve or a leaky drain valve, leaks can also come from pipes above the heater or from condensation on the unit.

Plumbing Pipes Above the Heater

Leaks from pipes above the water heater might seem like they're coming from the heater itself. It's important to check the plumbing system around the heater to make sure the leak isn't from somewhere else.

Condensation and Other Water Sources

Condensation on the water heater can look like a leak. This happens more often in humid areas or when the heater is in a cool, damp spot. The condensation can make it seem like the heater is leaking. Other water sources, like a leaking pipe or fixture, can also make it seem like the heater is leaking.

To figure out where the leak is coming from, you need to check the water heater and the plumbing around it closely. By checking these areas, you can find the real cause of the leak and fix it.

How to Diagnose a Water Heater Leak

Diagnosing a water heater leak is straightforward but requires safety first. First, turn off the gas or electricity, the main water supply, and the cold water to the heater. This stops more water damage and keeps you safe while you inspect.

Safety Precautions

When dealing with a water heater leak, safety is key. Here are the steps to follow:

  • Shut off the gas or electricity supply to the water heater.
  • Turn off the main water supply to the heater.
  • Shut off the cold water supply line to the heater.
  • Let the water heater cool down before starting repairs.
  • Wear protective gloves and eyewear to avoid potential hazards.

Locating the Leak Source

After ensuring safety, start finding where the leak is. Look at the heater's parts like connections, valves, and the tank for any water signs or dripping. Try tapping the tank to check for cracks or damage.

If you can't see the leak, inspect more closely. Check the drain valve, T&P valve, and connections where water might gather or drip.

By following these steps and being cautious, you can diagnose and fix your water heater leak safely.

Water Heater Maintenance Tips

Keeping your water heater in good shape is key to making it last longer and avoiding leaks. You should do two main things often: flush and drain the tank, and check the pressure relief valve.

Flushing and Draining the Tank

Sediment can gather at the bottom of your water heater tank over time. This sediment makes your heater less efficient and can cause it to fail early. To stop this, flush and drain your tank every year. This simple task takes about 10 minutes and gets rid of the sediment.

Checking the Pressure Relief Valve

The pressure relief valve, or T&P valve, is a vital safety device on your water heater. It opens and lets out pressure if it gets too high, stopping a tank from bursting. Make sure to test this valve every year to make sure it works right.

  • Check the valve by lifting the lever and ensuring it opens and closes properly.
  • If the valve is stuck or not operating as it should, it's best to have a professional plumber replace it.
  • The recommended pressure threshold for T&P valves in most tank-type water heaters is 150 pounds per square inch (PSI).
  • Typical temperatures that trigger T&P valve opening in tank-type water heaters are above 210°F.

Regular maintenance, like flushing the tank and checking the pressure relief valve, can make your water heater last longer and prevent leaks. By doing these things, you can keep your water heater working safely and efficiently for many years.

When to Replace vs Repair

As your water heater gets older, deciding to fix or replace it can be tough. The choice depends on how serious the problem is and the long-term costs. Knowing when to replace your tank and thinking about the costs and efficiency can guide your decision.

Signs of Tank Failure

If your water heater tank has a big leak or crack, it's likely time for a new one. Other signs include needing repairs often, finding rust in the water, and the heater not working well. If your water heater is over 10 years old, it might need to be replaced more often.

Cost and Efficiency Considerations

When deciding to fix or replace, think about the cost of a new water heater and how it could save you money. New, high-efficiency models use less energy, which can lower your bills. The cost of a new heater might be worth it if your old one is old and inefficient.

Some water heater brands offer long warranties, making replacement a good choice if your current unit isn't covered anymore. Making the decision to repair or replace should consider the heater's condition, your budget, and the chance for better energy efficiency.


Understanding why water heaters leak and doing regular maintenance can help homeowners fix the problem fast. This way, you can make your water heater last longer and save money on repairs or getting a new one.

It's key to find out where the leak is coming from. This could be a faulty valve, a leaky drain valve, or a tank issue. Regular checks and flushing can spot problems early. This lets you fix them before they get worse.

If you find a leak, check how serious it is and see if you can handle it. For small leaks, you might fix it yourself. But for big or complicated leaks, call a professional plumber. They have the right skills and tools to fix it right, keeping your water heater working well and safely.

Electric Heat pump outside
About Eco Heating & Air Solutions, Inc.
Residential and light commercial heating, cooling, air quality, and plumbing are specialties at Eco Heating & Air Solutions, Inc. We provide home and business owners in Oak Ridge, TN and surrounding areas free estimates, service of all makes and models, and trusted solutions to everyday requirements.

We are an eco-friendly, award-winning company and uphold Better Business Bureau accreditation. Our team of professionals is NATE-certified, drug-free, and dedicated to earning your approval and loyalty.


What are the common causes of a water heater leaking?

Common causes include an old water tank, drain valve issues, and high internal pressure. Malfunctioning temperature and pressure relief valves can also cause leaks. Loose or faulty connections and sediment buildup or corrosion in the tank are other reasons.

How can a malfunctioning temperature and pressure (T&P) relief valve cause a water heater to leak?

A bad T&P relief valve can leak if it's not installed or sealed right. High water temperature can also make the valve leak by causing too much pressure.

What can cause leaks at the drain valve of a water heater?

Over time, the drain valve can get loose or corrode, causing leaks.

How can a major crack or rupture in the water heater tank lead to a leak?

A big crack or rupture in the tank leads to a big leak. Sediment and corrosion can also cause cracks and leaks over time.

What are some other potential sources of water heater leaks?

Leaks can come from plumbing pipes above the water heater, making it seem like the heater is leaking. Condensation on the heater can also be mistaken for a leak.

What safety precautions should be taken when diagnosing a water heater leak?

To diagnose a leak, turn off the gas or electricity, the main water supply, and the cold water supply to the heater. Then, inspect the components carefully to find the leak's source.

How can regular water heater maintenance help prevent future leaks?

Regular maintenance like flushing and draining the tank to remove sediment helps. Checking the pressure relief valve ensures it works right. This can extend the unit's life and prevent leaks.

When should a water heater be replaced instead of repaired?

Replace the water heater if it has a major leak or crack. Frequent repairs and low energy efficiency are also signs it's time for a new one. Consider the cost of a new heater and energy savings when deciding to replace or repair.

Electric Heat pump outside
About Eco Heating & Air Solutions, Inc.
Residential and light commercial heating, cooling, air quality, and plumbing are specialties at Eco Heating & Air Solutions, Inc. We provide home and business owners in Oak Ridge, TN and surrounding areas free estimates, service of all makes and models, and trusted solutions to everyday requirements.

We are an eco-friendly, award-winning company and uphold Better Business Bureau accreditation. Our team of professionals is NATE-certified, drug-free, and dedicated to earning your approval and loyalty.

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