Is Your Hot Water Heater Leaking? Here's What To Do

Published onAugust 13, 2024
Appliance Maintenance and Care

Nothing can ruin a day quite like finding a puddle of water around your hot water heater. After all, they’re one of the most essential appliances used in a home.

Knowing how to identify and address the potential cause of the leak early on can save you from spending money on more costly repairs and keep your hot water supply flowing smoothly.

While there are some pretty obvious signs your tank has completely failed—like the puddle you found, corrosion at the bottom, or a leaking T&P valve—seeing water on the floor doesn’t always mean the leak is coming from your water heater.

There could be something wrong with your plumbing connections, the valves on the water heater, or even a vent pipe on top of a gas water heater.

In this guide, I’ll take you through the steps to tackle this problem head-on.

I’ll start by explaining how to identify the source of the leak, how to make minor repairs, all the way to knowing when the best solution is to call in the professionals.

Table of Contents

What To Do Immediately Once You Find Your Hot Water Heater Leaking

The moment you find your hot water heater leaking, you should look to stop the leak and make the situation safe.

Turn Off The Water Supply

Find the water shutoff valve near your water heater and turn it to the off position. This valve will be on the cold water supply line before it enters your water heater.

If it’s a gate valve, turn it slowly all the way to the right until it stops. If you have a ball valve, turn it against or perpendicular to the pipe.

Most valves will be near the water heater, but could also be located somewhere else in your plumbing system. If you don’t immediately see a valve near your water heater, look for a whole-house shut off valve.

This valve will be located where your water enters your house from your main water supply. In most cases, this will be in a crawlspace or basement. If your home sits on a slab, check inside a closet on the first floor.

If you still can’t find the shutoff valve, your last option would be to turn off the main water supply to your house.

If you’re on city water, you’ll need to turn the valve off at your water meter. If you have a private well, you should see a valve near your well pump or at your pressure tank

Turn Off The Power or Gas Supplying The Hot Water Heater

Once you’ve turned the water off, the next thing you need to do is turn off your hot water heater. If the leak is coming from inside your water heater, it will eventually drain the tank.

How fast that happens will depend on how bad the leak is.

Most newer water heaters have a water sensor that keeps them from running without a full tank, but these could fail, and you don’t want to take any chances.

If you have an electric water heater, go to your breaker box and flip the switch labeled water heater. If you have a gas hot water heater, turn the gas valve to the off position.

Water heaters that run without a full tank of water can cause overheating and seriously damage the heating elements, turning a small water leak into a much larger issue.

Contain The Leak

With your water and water heater now turned off, you can now try to limit water damage. Use buckets underneath any drips, and try to soak up any puddles around your water heater with towels or rags.

Make sure you look for standing water near any interior walls and completely remove the water off the floor. This is where the most damage is usually done.

Try and Locate Where The Leak is Coming From

To help you find the leak, wipe down your hot water heater and any water lines or connections around it, making sure everything is dry.

With everything dry, you should be able to see any new accumulation of water. If it’s not immediately obvious, there are a couple of places you should look first.

Common Areas Where Leaks Occur

Leaks at The Top of a Water Heater

Take a look at all the pipes and connections on top of your water heater. This includes

Where your water lines connect to the inlet and outlet (cold and hot) ports on top of the water heater.
Where any two pipes connect together with a fitting
At a shutoff valve.
Where an expansion tank connects to your cold water line.

Corrosion on top of the water heater is a strong indication there’s something wrong with the water lines or plumbing connections above it.

As water from the leak drips down, it can settle on the tank and create standing water that will eventually corrode the outer metal if left standing for a long time.

If you suspect the leak is coming from one of these areas but still can’t see it, grab some dish soap and rub it around each fitting and connection point. If water is leaking from any of these, bubbles will begin to form.

If you have a gas water heater with a vent running vertically through your roof, check if water appears to be dripping from the vent. This can happen when there’s a lot of rain in your area or if the vent cap at the top has become dislodged.

Leaks at The Bottom of a Water Heater

If you see water mainly at the bottom of your water heater or on the ground around it, the leak could be coming from a few places:

The tank itself
The drain valve
The T&P valve (relief valve)

Leaks From The Tank

If there’s a leak coming from the bottom of your water heater, you might have a more serious problem going on.

This usually happens with older water heaters (10+ years old) or when a lot of sediment has built up inside the tank.

Sediment comes from the cold water that enters your water heater. This water contains minerals like calcium and magnesium and other particles like salt, clay, and dirt that gradually settle at the bottom of your tank.

The time it takes your water heater to fill up with sediment will depend on the amount of particles in your water supply. The more particles there are, the “harder” your water is.

Homes using a private well system tend to have harder water than those that use city water because they’re pulling water directly from the ground.

When this sediment builds up inside a tank and sits for too long, it eventually starts to corrode the inner lining of the tank. Over time, this reduces the integrity of the tank and leads to leaks.

This is why tank manufacturers and plumbers recommend flushing your water heater once a year—and even more often if you have hard water.

The Drain Valve

The drain valve is located near the bottom of the tank. It’s used to flush out sediment and drain the tank. Sometimes, this valve can become loose or its components fail altogether, causing water to leak out.

Leaks tend to happen more often with plastic drain valves as opposed to brass valves because they crack easily.

To check if your drain valve is leaking, apply dish soap around where it enters the tank—just like you would with your plumbing connections.

Also, look for any dripping water coming out of the spout or leaks at the screw located on top of the spout that’s used to open and close the valve.

T&P Valve or Relief Valve

A T&P relief valve is a safety feature used on water heaters to release water if the temperature or pressure inside the tank gets too high.

This valve is usually located on the side or top of the tank, but the discharge pipe runs down to the floor, which can make it seem like the leak is coming from the bottom.

Check the discharge pipe for any signs of water. If the T&P valve is leaking, you might have too much water pressure in the tank, or the valve itself could be bad and need to be replaced.

How to Tell The Difference Between Actual Leaks vs. Condensation

Sometimes, it might look like you have a leak somewhere, but it’s actually just condensation.

Condensation can form on water lines and water heaters if they’re located in really humid areas or where temperatures fluctuate a lot like attics, basements, and crawlspaces.

If it’s just condensation, you’ll notice a fine layer of tiny water droplets on the outer surface of your pipes or near the bottom or top of your tank. These droplets typically spread pretty evenly across a surface, with a more uniform look compared to an actual water leak.

You also wouldn’t see any water pooling in the area. Condensation doesn’t drip consistently like a leak would.

Most of the time, you’ll be able to tell what’s a leak and what’s not. But to confirm the water you see isn’t a leak, just wipe off any water droplets and come back about half an hour later to see if any new water appears.

Quick Fixes for Minor Leaks

Once you’ve found the leak and know where it’s coming from, it’s time to figure out if it’s something you can fix or if you need to call a plumber.

Some leaks can be fixed quickly if you have the right tools and are comfortable making the repairs yourself. However, if you’ve confirmed the leak is coming from the bottom of your water heater or don’t have much experience with plumbing, call a professional to understand your options.

Depending on your experience, some simple DIY repairs might include:

Tightening connections
Replacing connections and pipe fittings
Removing and replacing sections of water lines
Changing out a bad T&P relief valve or drain valve

Before we talk about how to make these repairs, you need to make sure all the water has been drained from your water heater and removed from your water lines.

Draining A Water Heater

Start by locating the drain valve near the bottom of your water heater. It‘ll look just like a water spigot with male threads on the end.

Take a garden hose and tighten it to the valve just like you would a spigot outside your home. Then, take the other end of the hose and place it somewhere safe where hot water can be released.

If your hose can reach out into your yard, this is usually the best place for it. A floor drain will also work.

If your water heater is in an attic or in another location where your hose can’t reach out into your yard, place the end of your hose in a bathtub or out an attic window.

Just remember—the water draining from inside your water heater will be very hot. Make sure no one touches it to avoid scalding.

Don't place the end of your hose into any sinks or the drain pan underneath your water heater. Once your tank starts to drain, it should come out pretty quickly. Sinks aren’t usually deep enough to handle the flow, and the drain pan is only there to handle slower leaks.

Once you connect your hose and find a good release point for the water, you can now open the drain valve.

Using a flathead screwdriver, turn the valve slowly to the left to open it. Make sure to do this slowly. I’ve found that opening these valves too quickly, especially on older water heaters, can keep them from opening all the way.

Once opened, it might take a second, but you should start to see water coming out of the hose. If not, try opening the relief valve at the top of the water heater. This will release the pressure inside the tank and should allow your tank to drain.

Before opening the relief valve, place a bucket or bowl underneath the drain pipe to catch any water that may be released with the pressure. Also, the pressure being released might be loud at first but will start to fade.

If you’ve opened your relief valve and still don’t see any water coming out, you may need to hook up a water pump to help pull the water out.

This happens a lot with older water heaters that have never been flushed. The sediment at the bottom could be keeping the water from coming out.

Once you have a nice flow of water coming out of your hose, go to a sink or bathtub on the bottom floor and open up the hot side. This will help drain all the water from your water lines so you can work on them if needed.

Tighten Loose Connections or Fittings

If your leak is coming from one of the fittings used to connect your water heater to your plumbing lines, you can try tightening it. For most water heaters (whether it’s up to code or not), one of the following fittings is used:

Copper compression fittings
Brass fitting
PEX adapter
Copper solder adapters

If you have one of the first three types of fittings mentioned above, you should be able to tighten them. Here’s how:

Copper Compression Fittings

These fittings will have a brass nut on the end that connects to your water heater. You can tighten it by using an adjustable wrench and turning it clockwise. Do not overtighten this.

If you do, the copper tubing will start to kink, and you’ll have to replace it. If tightening doesn’t fix the problem, you can also take it off and check to make sure the o-ring inside is in good shape.

Just make sure you apply new Teflon tape and maybe even some pipe dope to the threads before hooking it back up.

Brass Fittings

Brass fittings are often used to add stability to a plumbing system. You might see these fittings used on the inlet and outlet water ports of your water heater or where an expansion tank has been installed.

They’ll usually have an adapter fitting on one side to transition to a different type of pipe. If you have a leak where one of these brass fittings connects to another, you’ll need to make sure that the fitting on the other side can also move or be loosened and removed before trying to tighten it.

To tighten these, you’ll need to “back up” the other fitting it connects into.

For example, if you have a brass fitting that’s used to connect to another piece of brass pipe, you’ll want to keep the pipe from moving when tightening the brass fitting.

To do this, position one adjustable wrench to tighten the fitting clockwise and another to hold the other fitting in place counterclockwise. Try to use two adjustable wrenches when you can, but you may need to use a Channellock on one end to keep a fitting from moving.

While brass hates being gripped by the teeth of a Channellock, it might be the only way you can back it up.

Pex Adapters

PEX adaptors are used to transition from brass or copper to PEX water lines. They’ll be connected using male or female threads and can be used anywhere in a plumbing system where the transition is needed.

This fitting should not be installed directly to a water heater’s inlet and outlet ports, but I’ve seen it before. If you see this on your water heater, it’s not up to code, so you really should be looking to change these out.

I’d recommend replacing them with a copper compression fitting that transitions to PEX on the other end.

Though it might not seem like it, these fittings can be tightened. Just like brass fittings, you’ll want to use adjustable wrenches when you can and make sure you back up the pipe or fitting it connects to.

You don’t need to worry if the PEX adapter inside your PEX pipe starts to turn when tightening. This is normal and should not affect the seal.

Copper Solder Adapters

Copper solder adapters will have threads on one end and a “cup” or “socket” on the other that’s used to solder and connect with another piece of copper tubing.

Because these are soldered together, you won’t be able to tighten them.

The only way to fix a leak on one of these fittings is to cut the copper tubing above it. Once cut, you should be able to turn this fitting off.

Most of the time, it’s better to just replace this fitting unless you have experience soldering pipes.

The key here is to avoid overtightening any fittings.

If you do, it can cause enough damage to the fitting where it would need to be replaced. Just turn them clockwise slowly until they feel snug.

For any threaded connections, it’s a good idea to apply a layer of Teflon tape around the threads before tightening.

This creates a better seal and will help prevent any future leaks.

After tightening, you can turn your drain valve off, disconnect your hose, and close your T&P relief valve. With everything closed, you can now turn the water back on.

Let your water heater fill completely so that your plumbing system has full water pressure. Watch closely in the same place you found the leak to make sure it stopped.

If this doesn’t fix the leak, you might have to replace the fittings, which is what we’ll talk about next.

Replacing Fittings, Plumbing Lines and Bad Valves

Sometimes, tightening a fitting or valve won’t fix a leak. If the leak was initially letting out a lot of water when you found it, you’ll probably save some time by just replacing what’s needed.

Replacing Fittings and Water Lines

Replacing a fitting or water line is a little more involved and will require certain tools and materials based on the type of water line you have.

The price for some of these tools may not be worth it for a one-time use. You can go out and buy them, but a local plumber will already have them.

Here’s a list of the tools and materials you’ll need based on the type of water line you have:

Type of Pipe	Tools Needed	Materials Needed
PEX	PEX Pipe Cutter and a Crimping Tool	PEX Crimp Rings and PEX fitting or Adapter
Copper	Tube Cutter. Torch, Deburring Tool, and an Emery Cloth	Flux, Solder, Copper Tubing, and Copper Fitting
CPVC	Tube Cutter – I recommend using this instead of a hand-held pipe cutter because CPVC tends to crack easily.	CPVC fitting (coupler, elbow, Tee, or adapter), CPVC Primer, and CPVC Cement
PVC	Ratcheting Pipe Cutter, PVC Shears, or Hacksaw, and Deburring Tool	PVC fitting, and PVC Primer and Cement (PVC primer and cement will be different than CPVC)
QUEST or Poly B	Pipe Cutter and Crimping Tool	Poly B Crimp Rings, Poly B fittings – these will look very similar to PEX but they’re not the same.

To cut out the area where your leak is occurring, use the appropriate cutting tool mentioned in the table above based on the type of pipe you have.

Once cut, you can remove the section where your leak is and replace it with new pipe and fittings.

When replacing adapters, make sure you also use Teflon tape on the fitting with the male threads. Adding an extra-thin layer of pipe dope will also help the seal.

Replacing a T&P or Drain Valve

When replacing a T&P relief valve or drain valve, you’ll need to make sure the new one is the correct size for your water heater.

For most residential water heaters, these valves will usually have ¾” threads that you screw into the water heater. However, you should always confirm this by either looking in the water heater manual or by contacting the manufacturer.

With the water turned off and the water heater fully drained, you can use an adjustable wrench or Channellock to remove these valves from the water heater.

Wrap the threads on your new valve with Teflon tape and add a thin layer of pipe dope—brushing it on in the same direction your tape is applied.

If you have a plastic drain valve, I recommend replacing it with a brass one. Plastic drain valves tend to leak a lot and crack easily.

If you don’t install them very carefully, they could crack before you even tighten them all the way back into your water heater.

When to Call in The Professionals

There are some situations where DIY repairs just won’t cut it. If you’ve tried tightening fittings and valves or even replacing parts, and the leak persists—or if the leak is coming from the tank itself—it’s time to call in a professional.

While you might think hiring a company will only lead to costly repairs, it could actually end up saving you money in the long run. Licensed professionals have the right tools and expertise to diagnose and fix the problem quickly and safely.

They should also be able to address any potential damage to electrical heating elements in your water heater, a gas burner under the tank, or any venting that needs to be fixed.

Just make sure you get multiple quotes. Some companies will overquote a job just because they don’t want to deal with it.

When to Replace Your Hot Water Heater

Giving your water heater a band-aid fix each time you have an issue can be frustrating and could get expensive. In some cases, replacing it will be cheaper than making multiple repairs to it, even if you’re making the repairs yourself.

Replacing your water heater won’t always be necessary when you see a leak, but it’s important to know when it’s time to do it.

Other than having a leak coming from the tank itself, here are some other signs that indicate your water heater is on its last leg:

Rusty Water

If you’re starting to see rusty water come out of your taps when using hot water, it could mean the tank is corroding from the inside out.

Once the corrosion starts, it’s only a matter of time before the tank develops leaks. Inside tank water heaters, there’s an anode rod that’s designed to attract and collect sediment so it can corrode before your tank does.

However, once the anode rod is fully corroded, the inner lining of your tank is next.

If you catch this early on, replacing the anode rod might extend the life of your water heater, but if the tank has already started to rust, replacing it is usually the best option to avoid inevitable leaks.

The Age of Your Water Heater

These days, tank water heaters only last around 10 to 15 years. If you have hard water, the lifespan of your tank could be even shorter.

It’s always a good idea to start thinking about a replacement at the ten-year mark. You might also want to think about buying a tankless water heater as these are more efficient and can last 20 to 25 years.

Strange Noises

If you hear any popping, rumbling, or hissing noises coming from your water heater, there’s probably a lot of sediment in your tank.

You can try flushing it out, but if you’ve never done it and you start to hear these noises, it might be too late. Once sediment hardens, it’s hard to remove.

Eventually, this will cause enough damage to the tank and create leaks that can’t be repaired.

Inconsistent Hot Water

Another clear sign that your water heater may be on its way out is if you start to notice you’re running out of hot water or feel your water temperature fluctuate.

This can be caused by a bad heating element or when the sediment in your tank has built up to a point where it starts to affect the efficiency of your water heater.

Maintenance Tips to Prevent Future Leaks

Regularly checking your water heater can help prevent leaks. Here’s a checklist of things to keep an eye on:

1. Check the T&P Valve

Test these at least once a year to make sure it’s working. Just remember to put something underneath the relief pipe to contain any water that might come out.

2. Inspect The Anode Rod

Check the anode rod every couple of years and replace it when it’s heavily corroded. To do this, turn your water off and drain about 5 gallons of water out of your tank.

You leave most of the water in the tank because you need it to be heavy enough to turn out the anode rod.

Next, locate the anode rod at the top of your tank. It’ll be covered with a plastic cap or insulation.

Inside, you’ll see the bolt that you’ll need to turn out to release it. Impact drills make removing these easier but you can also use a socket wrench.

3. Flush Your Water Heater to Remove Sediment

Flushing your water heater at least once a year is a good way to prevent sediment from building up and creating rust within your tank. Follow the steps mentioned above to drain and flush your water heater safely.

If you flush your water heater and see a lot of sediment coming out, you may want to flush it twice a year instead. You can also try adding a descaling solution to help flush the sediment out.

4. Water Pressure and Temperature Settings

Make sure your water pressure is set somewhere between 50 to 60 PSI. This amount of pressure provides a good flow of water without putting stress on your fixtures and water heater.

Also, make sure the temperature of your hot water isn’t too high. A standard residential water temperature is 120°F. Any temperature higher than that can reduce the lifespan of your water heater and may void the warranty.

5. Use Water Sensors and Leak Detectors

Install water sensors or leak detectors around your water heater or in the pan underneath it. These work well if your water heater is located in a spot in your house that doesn’t see a lot of foot traffic—places like an attic, basement, or crawlspace.

Some of these will send an alert to your phone, or you can get one that sounds an alarm when water is detected, giving you a chance to address the leak quickly.

Frequently Asked Questions

1. Is a Leaking Water Heater an Emergency?

Yes, a leaking water heater can be an emergency. Depending on how bad the leak is, it can cause a lot of water damage to your home, leading to costly repairs.

If the leak is coming from the tank itself, it may be severely corroded on the inside and at risk of bursting, which could result in flooding. While most modern water heaters have a safety feature to keep them from running without water, the water will continue to leak through until you notice it.

Address any leaks immediately by turning off the water supply and then try to find the source of the leak. Contact a professional plumber to diagnose and make repairs when needed.

2. Can You Still Use Water if Your Water Heater Is Leaking?

It’s not recommended to continue using hot water if your water heater is leaking. Doing so can increase the pressure within the tank, potentially worsening the leak or lead to a complete failure of the water heater. To avoid a much larger problem, turn off the water supply to your water heater and use cold water for your immediate needs until repairs are made.

3. What Causes a Water Heater to Leak from the Bottom?

A water heater leaking from the bottom can mean you have one of the following issues:

A faulty drain valve
A bad temperature and pressure relief (T&P) valve
Corrosion inside the tank.

The drain valve, located at the bottom of the tank, can become loose, leak through the seals, or become damaged over time, especially plastic drain valves. The T&P valve, which releases excess pressure, can also fail and cause water to leak out of the discharge pipe.

Finally, if the tank itself is leaking from the bottom, it’s usually a sign of internal corrosion, which often requires replacing the entire water heater.

Regular maintenance, like draining and flushing your water heater to remove sediment, a thorough inspection of the anode rod every couple of years, and making sure the water pressure and temperature are within recommended ranges (120°F and between 50 to 60 PSI) can help prevent these issues.