Why is My Water Heater Leaking?

Leaking water heater dripping from drain valve

If you find your water heater leaking, you need to take action immediately. A leaking water heater may seem like a minor inconvenience, but in reality, it can quickly turn into a major problem. The average water heater has a 50-gallon tank and whenever water leaves the tank (drawn or leaking) cold water will quickly refill it to capacity.

As the tank is constantly refilling from the water heater leak, the area surrounding your tank will flood. Even a small amount of water leaking from your water heater can cause damage to your floors, sub-floors and walls. A significant flood could lead to hefty repair bills and damage to personal property.  Water heater leaks can also be a health concern and lead to mold and mildew.

A water heater leak won’t go away on it’s own. Over time, it’ll get worse.

Not all water heater leaks are serious. Some can be repaired by simply tightening a connection. Others may need a little more attention, but you can probably do the repairs yourself, especially if you enjoy DIY projects.

Unfortunately, there’s also times when you’ll find your water tank leaking and you’ll either need to call a plumber to make the repairs, or purchase a new water heater.

Either way, this article will help you determine why your water heater is leaking and what you should do to resolve the problem.

Let’s get started!

Shutting off gas valve

Water Heater Leaking: What to Do First

If your water heater leak is not obvious, then you may want to do a little troubleshooting before turning off the water supply. Just because you have water under your water heater doesn’t mean that your water heater is leaking.

Furnace drain lines, water softener discharge lines, condensation, and other plumbing could be the source. These things can easily make it look as though your water tank is leaking, when in fact, the problem isn’t your water heater at all.

If you can’t identify where the water is coming from, you can dry the area and place some paper towels or newspapers down. Check back over the next couple of days. If the water returns, and you still can’t identify the source, there’s a good chance your water heater is leaking.

Dial valve on a copper pipe

Turn Off the Water Supply

The first thing you need to do is turn off the water supply to your water heater.

On top of your water heater there should be two pipes. One will be warm to the touch and the other cold. Some manufacturers even identify them with red and blue collars or paint.

The pipe that’s cold is the water supply line. It allows cold water to enter your water heater when hot water is drawn. Follow the line and look for a shutoff valve. Most water heaters have a shutoff valve on the water supply line.

How to Turn Off the Water

There are two types of valves commonly used:

  • Ball Valve – Ball valves have a lever type handle. Pull or turn the handle down to shut off the water supply.
  • Dial Valve – Dial valves (also called gate valves) have a wheel that needs to be turned clockwise to turn off the water supply. Turn the dial until it stops.

Although the majority of water heaters have a shutoff valve on their water supply line, some do not.

In this case, you may need to turn the water off using your home’s main shut-off valve. This will shut down all the incoming water to your house, including the water supply to your water heater.

Electrical Panel

Turn Off the Power

With your water turned off, it’s now time to turn off the power to your water heater. The process is different for gas and electric heaters:

Gas Water Heaters

Follow these steps to turn off the power to a gas fueled water heater:

How to Turn Off a Gas Water Heater

  • Locate the valve on the gas supply line. The line is usually within a couple feet of your water heater. It’s located near the bottom and connects to the gas control valve.
  • Turn the valve on the gas supply line clockwise until it stops. This will shut off the gas supply to the water heater.

Electric Water Heaters

Follow these steps to turn off the power to an electric fueled water heater:

How to Turn Off an Electric Water Heater

  • Locate the breaker to your water heater in the household electrical panel. It will be on a dedicated circuit breaker.
  • Flip the breaker to OFF.

Now with your water and power turned off, it’s time to roll up your sleeves and do some troubleshooting!

Corroded water supply inlet valve

Troubleshooting Hot Water Heater Leaks

Right now our goal is to identify the source of the water heater leak. Once you determine why your water heater is leaking, we’ll show you how to fix the problem.

As a general rule, when a water heater leaks from the top the problem can be repaired. In fact, you may be able to do the fix yourself.

Unfortunately, when your water heater is leaking from the bottom, there’s a greater chance that the problem is serious . . . but not always.

Here are some of the most common reasons a water heater leaks:

Top of water heater

Cold Water Inlet / Hot Water Outlet

If your water heater has a pool of water on top, there’s a good chance that the source of the leak is either the incoming water supply valve, cold water inlet, or the hot water outlet.

Whenever there are pipe connections, there’s a higher chance of a leak. Follow the cold and hot water pipes. Do you see any water? Are the fittings tight? Is there any leakage around the shutoff valve on the cold water supply line?

The fix to any of these problems could be pretty easy and you may be able to do it yourself. Here’s what to do.

T&P Relief Valve

T&P Relief Valve

The temperature & pressure relief valve (T&P relief valve) is a safety device required on all water heaters.

When pressure builds within the tank to an unsafe level, the T&P valve relieves the tank pressure by opening the valve and allowing some of the water out of the tank.

This will prevent the tank from bursting or exploding!

You can find the T&P relief valve on the top of your water heater or on the side. Look for a copper or PVC pipe that runs down the side of the tank towards the floor. This is the T&P drain pipe and it connects to the relief valve.

Since the T&P relief valve is a safety device, and if this is the source of your leak, it’s important that the valve is either replaced, or a plumber is called as soon as possible.

A T&P relief valve issue does not necessarily mean you’ll need to purchase a new water heater, but the leak does need to be addressed.

Once you determine that the problem is coming from the T&P valve we’ll do some additional troubleshooting to try to isolate the problem. If the solution is to replace the valve, we’ll show you how.

Rheem SP12112G Brass Drain Valve

Drain Valve

The drain valve is located near the bottom of the tank and is used to drain the water when repairs and/or maintenance tasks are required.

How to Determine if the Drain Valve is the Source of the Leak:

  • Verify that the drain valve is completely closed.
  • If the drain valve is closed, and there’s moisture coming from the drain opening, then the valve may be faulty and will need to be replaced.
  • Check the area around the drain valve where it enters the tank. There should be no signs of moisture. If you do have moisture where the drain valve enters the tank, it’s likely that you have an internal tank leak.

Unfortunately, many manufacturers install low quality drain valves in their water heaters, so it’s not uncommon for this to be the source of your leak.

Here’s what to do next if your leak is coming from the drain valve.

Leaky water heater tank on bottom

Internal Tank

Water heaters have a steel internal tank which is wrapped in insulation and then enclosed within an outer visible skin.

If the internal steel water tank is leaking, you won’t be able to see it by looking at the outer skin. In most cases, you’ll notice water under the water heater since the most likely way for it to escape is from the bottom.

When you were inspecting your drain valve and T&P relief valve, you may have noticed moisture where the valves entered the tank. If this was the case, there’s a good chance that your internal water tank is leaking.

Even with the best care, water heater tanks break down. Age and deterioration takes a toll and eventually the tank will begin leaking.

There are preventative measures you can take such as, treating hard water and performing regular maintenance, but eventually the inevitable will happen and you’ll have a leaking water heater.

If your internal tank is leaking, your options are pretty limited.

Blue prints with plumbing tools

How to Repair a Leaky Water Heater

If the problem appears to be minor, and you have experience doing your own home plumbing repairs, you may choose to fix your leaking water heater yourself.

But many homeowners are more comfortable hiring a plumber to make the repairs. The decision really depends on your comfort level and the complexity of the repairs.

Top of a gas water heater

Cold Water Inlet / Hot Water Outlet Repairs

If you have a leak coming from the area where the cold water inlet or hot water outlet connects to the water heater, you may be able to fix it by tightening the connections with a pipe wrench.

If tightening the connectors doesn’t stop the leak, then you should replace the flex lines that supply the cold water (or hot water). The video below will show you how.

Contact us for more information.

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