What to Do If Your Water Heater Is Leaking: A Step-by-Step Guide

If you ever notice a puddle of water under your water heater, it’s important to find out what’s going on. Water leakage can be a sign that there is something wrong with your water heater that needs attention. 

There’s no need to panic if you spot a leak, just follow our troubleshooting steps and you’ll be fine! 

1. Rule out condensation
2. Turn off the power supply
3. Turn off the water supply
4. Find the source of the leak
5. Address the leak
6. Prevent future leaks

Keep reading and we’ll better explain each step. We also have some helpful tips and insights on how to maintain your water heater so that you can avoid any costly repairs in the future.

Here’s what to do if your water heater is leaking:

Step 1: Rule Out Condensation

Before you assume the worst, take a breath. That puddle might not actually be a leak. Condensation is a surprisingly common culprit and worth ruling out first.

For gas water heaters, wipe up the water, turn the gas control valve to OFF, and wait a few hours. If the floor stays dry, condensation was likely the cause.

For electric water heaters, wipe down the outside of the tank and watch whether moisture returns in an even pattern across the surface. If it does, that’s condensation, not a leak.

Also take a quick look around the room. If your HVAC system, furnace, AC unit, or water softener lines share the same space, make sure the water isn’t coming from one of those instead.

Step 2: Turn Off the Power Supply

Once you’ve confirmed the water heater is the source, your next move is cutting the power. Water and electricity are a dangerous combination, so don’t skip this step. If you aren’t comfortable working with gas or electric water heaters then now is a good time to call in a professional. Leave gas piping to the experts!

For gas heaters, look for the shut-off valve near the top of the unit. There are usually instructions printed right on the front of the heater. Turn the knob or lever to the OFF position.

For electric heaters, head to your electrical panel and switch the water heater breaker to OFF. If the breakers aren’t labeled, check the diagram on the inside of the panel door.

Related: Gas vs. Electric Water Heaters – Which Should You Choose?

Step 3: Turn Off the Water Supply

Next, shut off your water supply to stop any further leaking. Your main shutoff valve is usually in the basement or near the street by the curb.

You’ll also want to shut off the cold water supply line going directly into the heater. Look for two valves on your unit, one typically marked in red for hot and one in blue for cold. Turning off the cold supply prevents more water from entering the tank while you figure out what’s going on.

Step 4: Find The Source of Your Leak

Now that everything is safely shut off, it’s time to play detective. The location of the leak usually points directly to the cause, so start by looking carefully at where the water is coming from.

The most common causes of a leaking water heater are a damaged pressure relief valve, loose pipe connections, a worn drain valve, a failing anode rod, or in more serious cases, a cracked or corroded tank. We’ll walk through each location below so you can narrow it down.

Step 5: Address the Leak

Water Leaking From The Top

Pooling water from the top of your water heater could be your cold or hot water inlets that bring water into the tank to be heated and then out into your pipes when you need it. Loose pipe connections can cause leaking from the top of your water heater.

Solution: 

• Tighten the cold and hot water inlet pipes with a pipe wrench, starting by hand and then snugging them up about a quarter turn more.
• Be careful not to overtighten, as this can crack the fitting.
• If the connections look corroded or the threads are damaged, replace the fittings entirely rather than trying to seal them.
• If tightening doesn’t stop the leak within a few minutes, the inlet valve itself may be faulty and worth having a professional inspect.

Water Leaking From The Side

Water leaking from the side of your heater is likely your temperature pressure relief valve (T&P valve). This is a safety mechanism that allows hot water and steam to discharge from the tank when there is too much pressure built up inside it. You’ll usually find it on the upper side of the tank with a small discharge pipe running down toward the floor.

Solution: 

• Check that your thermostat isn’t set above the recommended 120 degrees Fahrenheit, since excess heat causes pressure to build and triggers the valve to release water.
• If the temperature is set correctly and the valve continues to drip or leak, it’s likely worn or defective and needs to be replaced.
• This is a relatively affordable repair, but don’t put it off since a faulty T&P valve is a safety risk.
• If the water is coming from the discharge pipe specifically rather than the valve body, pressure is building inside the tank and you should call a professional promptly.

Water Leaking From The Bottom

If you notice water leaking from near the base of your water heater, it could be an issue with the drain valve. The drain valve is located near the bottom of the tank and is designed to empty the water when needed, such as during a flush or maintenance.

Solution:

• Inspect the drain valve for visible corrosion, mineral buildup, or cracks.
• If the valve looks intact, try tightening it gently with a wrench, but stop if you feel resistance since overtightening can crack the valve body.
• If tightening doesn’t stop the drip, the valve seal is likely worn and the valve should be replaced. Replacement drain valves are inexpensive and widely available.
• If the leak is coming from the tank itself rather than the valve, that points to internal corrosion, which unfortunately means the tank needs to be replaced entirely.

Step 6: Avoid Future Issues with Regular Maintenance

If your hot water heater is leaking but not showing any of the issues listed above, it may be due to a build up of sediment or mineral deposits. It’s important to flush your water heater annually as part of regular maintenance and preventative care. This can help avoid the need for costly repairs due to build up and reduce the risk of a leak.

To keep your hot water heater running efficiently, you should also check it regularly for any signs of leakage or damage. If you do notice a problem, contact a professional immediately to assess the issue and make sure your hot water is safe to use.

By taking the time to maintain your water heater and check for any signs of damage, you can avoid costly repairs due to a leaking system and keep your hot water running smoothly.

Additional reading: How Long Do Water Heaters Last?

Frequently Asked Questions

Is a leaking water heater dangerous?

It can be. A small drip from a loose fitting is usually low risk, but a faulty T&P valve or any leak near electrical components should be taken seriously. When in doubt, shut off the power and water supply and call a professional.

Can I take a shower if my water heater is leaking?

For a minor drip from a loose connection, probably yes in the short term. But if the leak is significant, near electrical components, or coming from the tank itself, hold off until the issue is fixed.

What should I do if my hot water heater is leaking from the top?

It’s most likely a loose inlet connection. Try tightening the fittings with a pipe wrench. If that doesn’t stop it, the inlet valve may need a professional look. See the Water Leaking From The Top section above for a full walkthrough.

What should I do if my water heater is leaking from the bottom?

Start by checking the drain valve for corrosion or damage and try gently tightening it. If the leak continues, the valve likely needs replacing. If water is coming from the tank itself, internal corrosion may mean it’s time for a new heater.

Why is my hot water heater leaking from the overflow pipe?

This means your T&P valve is releasing pressure, which could be due to a high thermostat setting, a worn valve, or genuine pressure buildup in the tank. The last scenario is the most serious, so call a professional if you’re unsure.

What are the signs that my hot water heater is going out?

Watch for rusty water, rumbling or popping noises, inconsistent water temperature, and visible corrosion on the tank. If your heater is over 10 years old and showing any of these signs, get a professional assessment.

Please contact us if you have additional questions about your water heater or our services. We’ve been serving the Portland area for over 70 years, and as one of the few remaining family-owned businesses in the area, we’re proud to serve our neighbors and community.