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How to Fix a Water Heater Leaking from the Top

john c flood water heaters

When your hot water heater leaks, you’ll usually find that leakage from the top is not as big of a problem as when the heater leaks from the bottom. Both types of leaks are serious, but if you’re going to face a leak, leaking from the top is the best scenario to find yourself in. 

Water leaking from the top of the water heater is almost always a repairable issue and doesn’t usually indicate that a replacement is necessary. If ignored, however, even this type of lower risk leak can lead to more serious problems and create expensive damage. Fixing the problem quickly is important.

Here are eight reasons why your hot water heater may be leaking from the top and how to solve each problem. 

1. Cold Water Inlet Valve

Problem: A cold water inlet valve is where cold water from the main water line enters your water heater. A pool of water on the top of your water heater can be an indication that the hot water heater is leaking from the top hot water outlet or inlet pipe. Always check the inlet pipe first, since this is more likely to be causing the water leakage. Something may have loosened, the valve may not be fitting properly, or the valve could have corroded.

Solution: Check the cold water inlet pipe and look for either a ball or gate valve that allows you to shut off the water. Check the valve for any signs of leakage. If you notice the pipe fitting has loosened and water is leaking from the valve, tighten it with a wrench. If the valve is still leaking after tightening, then the valve is likely faulty and will need to be replaced to prevent your hot water heater from leaking from the top hot water outlet or inlet.

2. TPR (Temperature and Pressure Relief) Valve

Problem: The TPR valve is typically located on the side of your tank, though it could also be located on the top. The purpose of this valve is to help release water, lowering the pressure in the tank if the temperature or pressure ever gets too high. If you notice water leaking out of the threads on the TPR valve, it will need to be removed to determine the source of the issue.

Solution: Look for any corroded or loose fittings on your TPR valve. If the valve is the source of the leak, it will likely need to be replaced with a new valve. The TPR valve is highly important in maintaining the safety of your unit, so you should not operate your hot water heater with a faulty TPR valve. Doing so could risk a hot water heater explosion.

3. Anode Rod Port

Problem: The anode rod is a long, thin rod inside your hot water heater that helps protect your hot water heater from corrosion. Over time, the corrosive agents inside the water would “eat” the inside of your hot water heater if the anode rod were not there to attract them first. The anode rod is used so your hot water tank doesn’t corrode, but if the anode rod isn't replaced, the corrosion will reach the top of the rod and bubble up. This could make your hot water heater leak from the top.

Solution: If your anode rod is the culprit, it will need to be replaced with a new rod. If you don’t get the anode rod replaced, then the hot water heater itself will begin to corrode, leading to far more expensive repairs down the road—even a full replacement.

4. Loose or Corroded Pipes Fittings

Problem: The problem could simply be due to loose or corroded pipe fittings. This can happen naturally over time as your unit is used and often isn’t a huge problem.

Solution: Check your water heater’s inlet and outlet fittings: the dielectric nipples. These nipples have a tendency to become loose or corroded over time. If they are simply loose, then they will need to be properly tightened. If there is corrosion, however, they will need to be replaced. When you see corrosion on the fittings, it’s important to conduct a more thorough examination of your hot water heater. Exterior signs of corrosion and rust could mean there is a serious internal issue and your unit could need to be replaced. That, or the fittings will simply need to be replaced.

5. Leaking Expansion Tank

Problem: Most hot water heaters are installed alongside a smaller tank that is called an expansion tank. The expansion tank typically sits up to the side of your hot water heater. Its purpose is to collect excess water coming from your hot water heater. As water heats up, it expands, meaning it will outgrow the space within your hot water tank. The water goes up into your expansion tank to help lower pressure levels inside your hot water heater. Over time and use, the expansion tank can start leaking.

Solution: Inspect your expansion tank and hot water heater to identify the source of the leak. Check the pipe fittings on the expansion tank and tighten any loose, leaking fittings with a wrench. If this doesn’t resolve the leakage or if the leak is coming from the expansion tank, then the expansion tank will likely need to be replaced.

6. Hole in the Top

Problem: Corrosion is a real problem with hot water heaters, especially if you don’t keep up with replacing your unit’s anode rod. Your hot water heater tank can corrode from the inside out, resulting in a hole on the top of your hot water heater where it is able to leak.

Solution: Unfortunately, if you find any rust or corrosion on the inside or top of your hot water heater—especially an amount that leads to a hole in the top of your tank—your hot water heater will need to be replaced.

7. Condensation

Problem: Sometimes when you find moisture on your hot water heater, the problem isn’t a leak but rather condensation. Essentially, condensate is airborne water vapor chilled below the dew point (the temperature where water vapor becomes a liquid). When low-temperature water comes into your piping and the heating process begins, your hot water heater can create up to a half-gallon of water vapor per hour of operation. This can create a lot of condensation on your unit.

Solution: Finding condensation on your unit is not a problem that needs to be fixed. It is a normal part of hot water heater operation. If you find moisture on your hot water heater, make sure to inspect it thoroughly to be sure it isn’t a leak. If it’s just condensation, there is no need to worry about it.

8. Rainwater

Problem: Rainwater can collect on the top of your hot water heater, especially after severe storms with heavy rainfall. Many homeowners mistake this puddle of water for a leak in their hot water heater.

Solution: If rainwater collects on the top of your hot water heater, this is not a serious problem. However, the water should be removed to prevent any corrosion from occurring. It’s also important to remove the water to be sure it was caused by a rainstorm and not a leak in your hot water heater.

How to Prevent a Water Heater From Leaking at the Top

Preventing your hot water heater from leaking is one of the best ways to protect your home from serious damage and expensive repairs. Most hot water heaters are hidden away in basements, garages, or utility closets, so it can be easy for a big leak to go unnoticed. 

That’s why it’s so important to get your hot water heater inspected and tuned up regularly by a professional. Regular maintenance on your home’s hot water heater can help prevent breakdowns and leaks, helping you save money on costly repairs and water damage in the long run.

Additionally, you can install a leak detector on the floor near your hot water heater to help alert you at the earliest signs of a leak. These devices let off loud signals and some can even be synced with your home’s internet to send you alerts if a leak occurs. 

Call Professional Plumbing Services to Fix Your Water Heater Leaking from the Top

If your hot water heater continues leaking from the top despite the fixes you make, don’t waste any time and call in a professional plumbing service right away. All leaks—even hot water heater leaking from the top—are serious issues that need to be addressed quickly to help prevent serious damages from occurring. Contact John C. Flood today to get all your hot water heater questions answered and schedule your service