8 Common Reasons for your Water Heater Leaking

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Water Heater Leaking

A leaking water heater can be caused by many things, including broken or faulty valves, water line connections, corrosion, and even faulty or old pipes.

Once you spot a leaky water heater, you should call a technician immediately. Broken water heaters, while extremely rare, have the potential to kill. The water heats up and builds pressure within the tank, which normally releases from a safety valve. 

However, the leak won’t coordinate with the safety valve, which poses a great danger. Without the release, the appliance could explode in rare cases.

8 Reasons for your Water Heater Leaking

  • Corrosion
  • Loose Water Line Connections
  • Broken Pressure or Temperature Valve
  • Drain Valve Issues
  • Damaged Water Inlet Valve
  • Loose Pipes
  • Damaged Tanks
  • Normal Wear and Tear of your water heater due to age

What We will Cover

  • Why Do Water Heaters Leak?
  • How to Tell if Your Water Heater is Leaking
  • Don’t Try to Fix It Yourself
  • What to Do First
  • Why is My Water Heater Leaking from the Bottom?
  • Leaking from Inside the Tank
  • Leaks from the Top vs Leaks from the Bottom
  • Why Does My Water Heater Leak from the Top?
  • Leaks Due to Age and Deterioration of a Water Heater
  • Fix or Replace the Water Heater?

Why Do Water Heaters Leak?

Having a loose drain valve ranks as the most common reason that water heaters leak. You can spot a broken drain valve because the water leaks from the bottom of the tank. Luckily, a plumber can easily fix this by repairing the broken drain valve.

Some of the other causes of a leak on the water heater include:

  • Corrosion
  • Loose water line connections
  • Broken pressure or temperature valve


You can’t put an understatement on the seriousness of water heater corrosion. The whole system is at risk of weakening and failing. While we can’t necessarily say that you should replace a corroded water heater, there are many cases that may require you to replace it. 

This is especially true with gas water heaters, as the corrosion can impact the burners and the heat exchanger which in turn will reduce its effectiveness.

Water Heater Leaking

Loose Water Line Connections

Loose water line connections rank as the most common cause of leaks above the water heater. Over time, normal wear and tear can begin to loosen the inlet and outlet water line connections. 

Loose pipe fittings will cause the water to leak from the ends of it. You can replace the tubes much easier than you can the water heater, which doesn’t make it as serious of a problem as corrosion. In some cases, a plumber will simply tighten the line that became loose. 

It isn’t uncommon to find leaks near the threads of what plumbers refer to as the nipples at the top of the water heater. Threads can be found in the inlet and outlet pipes on the water heater. The cold water enters through the inlet pipe, and hot water exits through the outlet pipe.

Broken Pressure or Temperature Valve

The pressure and temperature valve monitors and regulates the pressure within the water heater. Leaks from the side happen when either of these valves break. As you can imagine, this can pose a danger when the temperature and pressure don’t get regulated. 

You can tell that you have issues with the temperature valve when the water consistently feels either too hot or too cold.

Don’t Try to Fix it Yourself

Most manufacturers of water heaters have said that they will void the warranty if the average person tries to fix the water heater themselves. For this reason, you should plumber” target=”_blank” rel=”noreferrer noopener sponsored”>hire a plumber to come in and fix the leak. 

Another danger is that water heaters work with scalding hot water, and they have the potential of posing a danger if not worked on correctly. 

What to Do First

When you first spot a leak, you want to turn off the power to the water heater and assess for the source of the leak. Does it leak from the bottom or the top? This can tell you a lot about what may be causing the water heater to leak.

  1. Check the Pressure Relief Valve
  2. Check Thermostat settings
  3. Check Inlet and Outlet valve
  4. Check Water Pressure
  5. Check Drain Valve
  6. Check for Corrosion

We already covered what could be wrong with it based on where it leaks. If it leaks from the top, for example, you may have a loose water line connection. If it leaks from the bottom, you likely have a loose drain valve. Broken pressure and temperature valves will leak from the sides. Finally, you can usually spot corrosion once it starts to happen easily enough.

After you have learned of the source of the problem, we would advise that you call a plumber for any repairs or replacing. You can tell the plumber where the issues are likely coming from. With a leaking water heater, where it leaks will usually tell you a lot about what causes the leak.

Why is My Water Heater Leaking from Bottom?

A water heater that leaks from the bottom has a high chance of being a serious problem. You can spot it leaking from the bottom because you will see a pool of water underneath the water heater. Think of that as the first sign of trouble, and you need to resolve it as soon as possible to keep from further headaches. 

water heater leaking from bottom

Temperature and Pressure Relief Valve

We spoke about how this often happens as a result of a broken drain valve, but the temperature and pressure relief valve could also be the source of the problem. This is because of a discharge tube that runs between the floor and the valve. 

The discharge tube safely eliminates leaks from the valve to direct them downward and away, instead of it spraying outward, which could cause third-degree burns. 

Check the discharge tube for moisture. If you find moisture, the issue relates to the pressure and temperature valve. Either you have a faulty valve, or you have too much pressure in the tank. 

Drain Valve

The drain valve is another common reason for a water heater that leaks from the bottom. You need to drain the tank regularly to remove sand from within. Failure to remove the sediment will eventually damage the inner part of your tank. 

The drainage valve drains the water at the bottom of the tank before replacing the tank or for maintenance. 

The leaks that start at the nozzle may prove as simple as closing it fully. Tightening the knob may do the trick, but if that doesn’t work, you have a faulty drainage valve that requires calling a plumber to replace it. 

You may consider buying a water sensor alarm and installing it near the water heater to stop future leaks. It only costs between $25 and $80, but it can save you a lot of money if the water heater springs a leak.

Leaky Drainage Valves Worsen with Time

Leaving a valve that no longer has a water tight seal , will only worsen over time and increase the chances of having a damaged water heater that poses a risk to you or your home. As such, calling a plumber to have them replace it is a critical step to resolving the problem.

How Often to Test Your Valves

Homeowners should test their valves every six months to see that they continue to function correctly. You want to see that the water exits the tank from the valve, and you also want to check for corrosion. 

Most plumbing companies advise that you replace your temperature and pressure valve every five years to ensure that the water always exits from the valve correctly.

You can tell when your pressure valve has gone bad because it may display one or more of the following signs:

  • Leaking
  • Flooding
  • Debris in water
  • Excessive noise
  • Ruptured tank

If your water heater has one of these signs, call a plumber as soon as possible because this is the likely cause. Replacing a drainage valve will cost anywhere from $10 to $30, not counting labor.

Leaking from Inside the Tank

Many leaks come straight from the tank of the water heater. Usually, this will cause a slow leak that pools out of the device. This type of leak happens because of an amassing of sediment within the tank. 

If you don’t drain the sediment regularly, it will cause the steel container to rust and crack. Eventually, a leak begins to develop, and this always ends in a need to replace the water heater.

Leaks from the Top vs Leaks from the Bottom

While it can be disconcerting to see either a leak from the top or the bottom, we would say that a leak from the top doesn’t pose the same danger as a leak from the bottom. In most cases, it may be less serious. 

You can remedy the problem in all cases when it leaks from the top, whereas leaks at the bottom have a higher chance of you needing to replace the water heater altogether.

Why is my Hot Water Heater Leaking from Top?

Water heaters may leak from the top for a few reasons, one of which we have already highlighted above. Leaks from the top may pose less risk that you would need to replace the water heater altogether, but that doesn’t mean that you shouldn’t take it seriously. 

Every leak has the potential to cause danger to you or damage to the home if not addressed quickly. 

First, you need to home in on the source. Shut off the power supply and check the thermostat of gas control water heaters to see that they have turned off. You want to leave the cold water inlet on so that you can diagnose the source of the leak. 

While you want to turn on the cold water inlet, you shouldn’t leave it on for long. The whole point is to use that to find the leak. Once you find the leak, turn it off to stop any further damage.

Some of the most common reasons that a water heater leaks from the top include:

  • Damaged water inlet valve
  • Malfunctioning Temperature and Pressure Valve
  • Loose Pipe
Water Heater Leaking from bottom

Damaged Water Inlet Valve

Normal wear and tear can cause the inlet valve to leak, but in some cases, it happens because of a faulty component or damage to a component. 

You will want to check the valve to see if that caused the leak. If so, speak with a plumber to have them replace it. In some cases, you can simply tighten the valve to stop the leak, but if you tighten it and it still leaks, you may need to replace it.

Malfunctioning Temperature and Pressure Valve

Perhaps one of the most common reasons for leaks at the top of the water heater, this often happens because the valve either was damaged, or it began to malfunction. Sometimes, you will also hear this called a temperature-pressure relief valve. 

Usually, this valve will cost less than $15, and the plumber will remove the water from the heater, remove the discharge and replace the valve. It doesn’t require much more work than that. 

This valve will begin to malfunction for a variety of reasons, such as excessive pressure or temperatures. In some cases, the valve itself may have a defect. The valve operates as a safety relief mechanism to release excessive temperatures and pressures.

Loose Pipe

Loose pipes may also cause a leak at the top of the water heater. You will need to tighten the pipe and the connection points wherever it seems to be leaking. 

Over time, these components may begin to corrode, which may require a replacement of the components. If the tightening didn’t stop the leak, you will also need to replace the components. Leaks from the base where it screws into the water heater will also require a replacement of those components. 

A water heater leak from the top doesn’t pose as much danger as those from the bottom, but you still need to address the problem as quickly as possible. Small leaks can quickly turn into costly flooding that may damage your subfloor. 

To give you an idea, it costs between $450 and $2,000 to replace an entire subfloor, which doesn’t account for replacing the finished flooring.

Leaks Due to Age and Deterioration of a Water Heater

Water heaters will last anywhere from 6 to 13 years, but you should consider anything after 12 years to be on borrowed time. Gas water heaters may last an additional 2 to 5 years. 

You may want to start financially preparing to replace it before it starts leaking or causes damage. The lifespan of your water heater will depend on the water that runs through it, and whether you have kept up on maintaining it. 

You can usually spot it when it needs replacement because it will leak near the water heater. In some cases, it may make unusual sounds like gurgling or popping. Think of that as the sign that you need to replace it. 

Other signs besides leaking that show that you need to replace your water heater include:

  • Water heater over 12 years old
  • Strange color to the water
  • Lacking hot water
  • Dampness near the water heater

Fix or Replace the Water Heater?

Understanding when to fix a water heater and when to replace it is critical. Whenever the water heater won’t function normally or efficiently, you may want to consider replacing it. 

On the other hand, if fixing a simple part will restore the water heater to its original condition or efficiency, then you want to fix it.

Don’t think of buying a new water heater as all bad because in some cases, you will actually save money on water. Newer water heaters are made more energy efficient. 

Call a Plumber

You can figure out the source of the problem, but water leaks require the plumber” target=”_blank” rel=”noreferrer noopener sponsored”>expertise of a plumber who understands how to work on them properly. Trying to fix serious water heater issues yourself may cause more damage and ultimately void the warranty on the heater itself.

The H2Home Lab team is dedicated to helping you find the best solutions to your specific water needs, as well as provide troubleshooting tips and guides for water filtration, heating, softening and plumbing. We hope you will find the info you need on our site from any one of our buying guides or subject matter articles.

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