Why my Water Heater is Leaking from the Bottom? Troubleshooting and Repairing Tips

Gas water heaterGas water heater (photo: Rheem)

Q: Why my water heater is leaking from the bottom? How do you stop a leak? Should I turn the unit off?

A: The easiest way to stop the leak is to turn off the water supply on the shutoff valve installed on the cold inlet pipe.

If your water heater is leaking from the bottom, be cautious, this might be a serious issue. A leak from the bottom of your hot water tank means that there's a problem either on one of the components, connections, or the tank. One of the first signs you might notice is a puddle of water beneath your water heater.

So let's see what you can do about this problem, can you take a shower if it is leaking, and is it dangerous.

In general, there are several reasons why your water heater is leaking from the bottom. This is not an uncommon problem and can often be mixed up with the leak from the top.

We'll look at some of these reasons in a while. If you notice a leak, don't just ignore it, it is recommended to:

  • Find the cause of the leak.
  • Prevent additional water damage as much as you can.
  • Turn off the gas, power, and water supply.
  • Decide on what to do next – fix the element, connection, or replace a water heater.

To turn the power off on the electric water heater, find the circuit breaker and flip the breaker to OFF.

To turn the power off on the gas water heater, locate the gas shutoff valve installed on the heater's supply line and close it (the valve handle should be perpendicular to the gas line).

Use the shutoff valve installed on the cold water supply to close the water delivery to the tank.

Signs that show your water heater is leaking from the bottom

To avoid personal injury and property damages, it is important to know the signs of a leaking water heater. Here are some:

  • No hot water from the faucets
  • Loss of pressure in the faucets
  • Puddle of water at the base of the unit
  • Wet or stained surfaces on ceilings and drywalls

Is leaking from the tank dangerous?

In most cases, minor water heater leaking is not dangerous, but it all depends on the size of the leak and location.

Tanks installed in the attic are especially dangerous when they develop a leak because they can flood all the rooms and living space on the lower floors.

If left untreated, wooden objects and drywalls can get wet and develop mold and mildew.

If the tank water is scalding hot, you might get burned once in contact.

If the problem is small, you can still take a shower, but be careful. Limit water usage until your plumber arrives and repairs or replaces your water heater.

The reasons why your water heater is leaking from the bottom

Now, there are many reasons why your gas or electric water heater could be leaking from the bottom. Whether you need minor repairs or a complete replacement - it all depends on where you find the leak. Below are a few places where a water heater might be leaking and the causes. We'll also show you what to do about the leak and prevention, so you can save the property from further water damage.

Temperature & pressure relief valve (TPR) is leaking

T&P valveT&P valve (photo: AO Smith)

Generally, one problem area when it comes to leaks from the bottom of the water heater is the temperature and pressure relief valve or short - TPR valve.

The TPR (also known as T&P) valve is a safety device installed in the hot water tank.

It releases hot water and lowers the pressure when the water in the heater gets too hot and when there's too much water pressure in the tank. It has a discharge tube that runs from the water heater valve and ends a few inches from the floor.

Now, the job of the discharge tube (also known as the overflow pipe) is to keep leaking water from spraying outward on to nearby objects or people. It does this by directing water discharge or leaks from the valve downwards and safely to the drain. So, if you notice water at the bottom of your hot water tank, check the discharge tube and if it is releasing any water.

Consequently, you may need to replace the TPR, tighten the connection, or get a plumber to fix the problem. Note that it is important to get this repaired quickly because running hot water without the TPR is dangerous. Also, do not try to fix the valve, replace it, because it is safer. Or, you might simply need to reapply the Teflon type or pipe dope.

A leaking or faulty drain valve

drain valveDrain valve (photo: AO Smith)

Another reason why your water heater is leaking from the bottom could be a faulty drain valve. The drain valve is found at the bottom of a water heater. It is used to flush or drain the water in the tank during routine maintenance.

Of course, it is important to mention that you should drain your tank regularly to get rid of the sediment buildup. If left unattended, these sediments could reduce the efficiency and performance significantly or even worse - damage a water tank and other elements.

emergency plumber

How does a faulty drain valve cause a water leak?

Sometimes, it could just be that the drain valve is not completely closed. If you notice that water is leaking through the spigot, just tighten the knob, and it might stop leaking.

However, after tightening the knob, the outlet might still be dripping water. If that happens, then the drain valve is faulty or clogged and needs attention. Check out this guide on how to replace a drain valve.

Leaking from the inside (condensation in the combustion chamber)

Another area where leaking could occur is where there's condensation. It is more noticeable when temperatures are at the lowest in early spring and winter.

For example, condensation occurs when an empty hot water tank is suddenly filled with cold water.

A perfect example of this is with a glass of ice water on a hot day.

Therefore, filling a water tank with cold water when the burner is on could cause condensation. The combustion process produces moisture, which then condenses on the cooler surfaces of a water tank. When the condensate, such as water droplets, falls on the burner and other hot surfaces, it produces a sizzling noise.

Excessive condensation could cause water to run down the flue tube and onto the main burner. When this happens, it obstructs the ignition system, resulting in the pilot outage. Also, this could make you think that a water heater has sprung a leak. However, giving it some time to warm up, this could fix the problem.

So, what exactly causes condensation?

Well, there are several reasons why condensation might occur in your water heater. Some of these include:

  • When the water heater is running for the first time and filled with cold water.
  • High demand for hot water, causing the tank to be refilled with cold water very quickly and in a short time.
  • Gas burns might produce vapors in high-efficiency models with lower flue temperatures.

Interestingly, any one of these conditions could make you think that the water heater is leaking from the bottom. One way to avoid these is to make sure that you correctly size a water heater. A water heater should be large enough to meet the hot water demands of your household.

It is essential first to check if the suspected leak is actually just condensation taking place. To do that, clean up the puddle of water that has collected beneath the water tank. Next, observe to see if the water reappears or not. If it doesn't, then it's simply condensation. However, if the water is still dripping even after the water in the tank has warmed up, the odds are condensation is not happening.

How to minimize condensation on a hot water tank

As such, if you want to avoid the problem of condensation, there are a few steps you can take.

  • Increase the air circulation around the tank, clean the flame arrestor underneath.
  • Reduce the level of indoor humidity using a dehumidifier.
  • Insulate the hot water tank using the insulation blanket (even pipes using the foam sleeves).
  • Add heat (to reduce the temperature difference between inside and outside) on the spot if condensation is persistent.

Leaking connections

Actually, when you suspect a leak, this is one of the first places to check. Often faulty or loose connections can cause a leak. So, it's a good idea to look through all the connections to the water heater to be sure that none is loose. You might also need to reapply the Teflon tape or pipe dope.

Leaking tank

Note that most of the leaks come from the hot water tank itself. A leaking tank is most often caused by the buildup of sediments in the tank and corrosion. This is why it is crucial to drain your tank regularly, therefore making it free of residues and make it perform as it is designed for. This will keep sediments from forming as this can cause rust and cracks in the metal tank over time.

Usually, a leak from the tank itself means the water heater will need to be replaced. In this case, you should get a plumber to investigate further, or you can simply get a new water heater.

If you don't want to avoid potential leaks of the tank-type water heater, you should get a tankless instead because it does not have a storage tank, and it rarely leaks. As opposed to tank-type heaters, tankless, even if it leaks, could be repaired because every element can be replaced – so there is no need to replace the whole unit.


If your water heater is leaking from the bottom, and the problem is not series and noticed on time, don't worry; it can be easily handled if you are handy with plumbing repairs.

Fixing the problem will go a long way to prevent further damage. If you can DIY, that's great because you will save money, but if not, get assistance from an expert

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