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Water heater leaking from the top? Here’s what to do

Your water heater is an essential part of your daily life. If you find there is low hot water pressure because your water heater is leaking from the top, you will need to act fast. The good news is that a hot water heater leaking on top may be fixable and can be pretty easy to do.

If you don’t repair it, the water could continue to leak, giving you a damp basement and potentially causing water damage to the whole area (we had water damage on our wood floors, and it wasn’t very good). Here is what you need to do when there is a leaking water heater from the top.


Steps to diagnose why the top of the water heater is leaking

We will need to diagnose the source of where the water heater is leaking out of the top of the tank. To do this, we need to follow these 3 steps for safety purposes.

Step 1: Turn off the power

The top of the water heater is where the power comes in and also where the water comes in and out via the cold water inlet and the hot water outlet.

Turning off the power ensures that you won’t have any electrical issues.

Gas Water Heater Tank

If you own a gas water heater tank that is leaking, shut off the gas before working on the tank. There will be a dedicated gas shut-off valve on the line going into the tank. Simply put it to the off position.

Electric Water Heater Tank

If you have an electric hot water tank, the best thing to do is to turn off the power at the circuit breaker on your panel before doing anything with your tank. Simply find your electrical panel and turn it off.


Step 2: Turn off the cold water valve

Your water heater gets its water from the cold water supply. It should have a shut-off valve at the cold inlet. Turn the lever to the off position.

If your tank has a wheel on it, turn it clockwise until the water shuts off. At this point, you do not need to drain the tank. Once the water lines are off, you can take a closer look to see why your water heater is leaking from the bottom.


hot water tank leaking

Step 3: Inspect the top and source the water leak

The water leak will likely come from one of four places: the hot water outlet valve, the cold water inlet, the anode rod, or the temperature and pressure relief valve.


Causes of a top leak on your water heater

leaking water heater from top

Top of a water heater with T&P valve in the middle with cold and hot on the sides

Coldwater inlet pipe

The first place you will want to check is the cold water inlet valve.

This is where the cold water comes into your hot water tank to be heated. You can tell which one is the cold water because it will have a shut-off valve that you’ve turned off, and it may be etched into the top of the water tank.

First, inspect the cold water inlet to see if it’s leaking. If you notice that the fitting is loose, it is an easy water heater repair; simply tighten the fitting with a plumber wrench.

Take a look at all the connection points and see if any of the loose connections that need to be tightened. As the water tank ages, it’s normal for the pipe fittings to get loose or corroded. If that happens, you need to change the fitting.


Hot water outlet pipe

The next place to inspect is the hot water outlet pipe. This pipe is where all the hot water comes out and circulates through the house. It will be hot to the touch.  Look at the connections coming out of the tank and see if there is any water around the outlet pipe. If there is, it may need to be tightened.

If you do not have experience repairing your own plumbing, the best thing to do is contact a licensed plumber in your area.


Temperature and pressure relief valve

Another issue that can arise is that the temperature and pressure relief valve (T&P valve) on top of the hot water heater can wear out or become faulty.

In this case, the water will be coming through the valve’s thread, and you will need to remove it and inspect it to see if there is an issue. If you notice water leakage around this pipe, you will need to inspect it further.

Corrosion can happen on these valves. Remove it and see if the water is coming through because of that issue.

Replacing your T&P valve if it is faulty should happen right away. These valves are a safety feature on all hot water tanks to relieve pressure as it builds up inside the tank so that the pressure does not cause the tank to explode.

How to replace a TP Valve

To replace your temperature pressure and relief valve, you will need to drain the hot water tank so that the water level is below the TP valve. You can do this using the drain valve at the bottom of your tank. Make sure to close it tightly otherwise; you will have water leaking from the bottom of your water heater as well.

Next, turn on a hot water tap so that you can let air into the tank; use a pair of channel lock pliers to unscrew the valve and inspect the unit for rust or corrosion. If you do find rust, you will need to replace the water heater.

If there isn’t any rust, you can get some plumbers tape (Teflon tape) wrap it around the new valve thread so that it seals properly (usually five times around will do).

Then, make sure to work the tape into the grooves, then screw the valve back into the tank using the channel locks to tighten it. Turn the water back on and see if it is still leaking.


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Anode rod port

The anode rod is a long rod that sits in the hot water tank to prevent it from corroding. Over time, your household water can have corrosive agents, which eat up the inside of the hot water tank. The anode rod is designed to attract those corrosive agents so that the water heater doesn’t corrode and lasts longer.

If your anode rod hasn’t been replaced and there is water leaking from the top of it, you may need to replace it. To do this, contact a professional to inspect your hot water tank as the corrosion may have done more damage at this point to your tank and may need to be replaced as a whole.

Related: How Long Does it Take to Install a Water Heater?


Commonly asked questions about a hot water tank leaking from the top

What would cause a hot water tank to leak from the top?

Your hot water tank will leak from the top for one of four reasons.

  1. The cold water inlet is leaking at the tank or above it due to a fitting corroding or wearing down.
  2. The hot water outlet is leaking, and it’s due to corrosion or loose-fitting.
  3. The temperature and pressure relief valve is faulty, or the threat has come loose.
  4. The Anode rod needs to be replaced.


Is a leaking water heater dangerous?

A leaking water heater can be a symptom of a much bigger issue. As a rule, do not let your hot water tank keep leaking for too long because this can cause water damage throughout the area of your house.

For this reason, we recommend having a hot water tank pan underneath the water heater without adequate drainage, so if the leak becomes excessive, the water will drain away properly without damaging your house.

Related: Water leak spread?  Here’s what to do if you have wet carpet in your basement.

Final thoughts on water heater leaking from the top

Most of the issues that arise from a water heater with a top leak can be fixed pretty quickly. The good news is that a good set of plumber pliers and some proper diagnosing will go a long way. However, if there are items that need to be replaced, it’s always a good idea to contact a professional plumber. If you need to hire, one you can use the link below to do so.


Click Here to Find a Local Plumber


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