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Is A Drain Pan Required Under A Water Heater?

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

Every home has a water heater, and it is an important appliance in any home.

It is known that a water heater supports a lot of water, which can cause serious damages to your home, if it happens to fail at any point.

The best way to avoid these damages is by installing a drain pan under your water heater. 

Over the years, the plumbing codes have changed every couple of years. However, one of these changes has meant that a drain pan is now a requirement.

However, sometimes the decision whether you need a drain pan can depend on where your water heater is.

In this article, we will be discussing when you are required to have a drain pan under your water heater. 

Drain Pan Under Your Water Heater Requirements

It can be confusing whether you need a drain pan under your water heater.

There are different requirements when you do a drain pan, and there are some scenarios where you aren’t required to have a drain pan either. 

Below we have put the plumbing code and explained the rules when a drain pan is required. 

Plumbing Code

504.7 Required Pan

When your hot water storage tank or storage tank-type heater has been installed in an area where the tank leak could cause damage.

Then in this case, a steel pan will be installed. It should be no thicker than 0.0236 of an inch, or another pan may be installed with approval. 

504.7.1 Pan Size And Drain

The pan itself should not be less than 11/2 or 38 mm deep.

It should also be a decent shape and size to be able to gather any drips or condensation that will be coming off the water heater or tank.   

Also, the pan can be drained using an indirect waste pipe. This pip should have a diameter of a minimum 3/4 of an inch, or 19 mm. 

504.7.2 Pan Drain Termination

The drain pan is required to extend the full size and terminate over an indirect waste receptor floor drain.

Or the pan drain can extend to the outside of the building and end a minimum of 6 inches and a maximum of 24 inches above the ground surface. 

If a pan drain has not been previously needed or installed. Then, when a replacement water heater is installed, a pan drain is still not required. 

Other Reasons To Install A Pan

Apart from what has just been said in the plumbing code, there are a couple of other situations when you may be required to have a pan installed. 

If your water heater is located above ground  level, in a ceiling area or attic.

You may be asked to install a pan when your water heater is placed inside your home in a living space. 

Now we will go into further detail why a drain pan will be required in these scenarios.

However, in some cases you may not have a choice whether you want to have a drain pan if your local building code states that they require drain pans for your water heater. 

Water Heater Located In A Attic Or Above First Floor Level

It is important to have a drain pan installed, if your water heater happens to be located on the first floor of your home.

Hence, if your water heater does happen to leak and there is no drain pan, then this leak could cause a lot of structural damage to your home.

Which then causes a large bill to fix those damages and repair or replace your water heater. 

If your water heater happens to leak in a multiple level home, then the water will drip through all the ceilings and walls.

This can then cause damage to the structure of your home.

Whilst also making the perfect breeding ground for mold to grow and develop, which will also need to be removed and cleaned. 

If you do suffer a large leak to your water heater that is on an upper level. Then you need to discover whether the leak is damaging the load bearing wall of your house.

This is because, if you don’t check and there is damage, then there are chances of parts of your house collapsing.

Or in the worst case scenario, your entire home could fall down. 

As a result, we would recommend that you don’t install your water heater high up. Instead, install your water heater as low in your home as possible, like the basement.

This way, if your water heater does leak (see also ‘Why A Water Heater Leaks From The Overflow Pipe‘), the water won’t cause any major damage to your home or the structural supports.

Water Heater Is Located In A Living Area

Water Heater Is Located In A Living Area

Not every home is able to install their water heater out of the way, like in a basement.

Instead, the water heater (see also ‘Can You Transport A Water Heater In A Car?‘) has to be installed in a living area, which is often used by the household for other activities. 

As a result, in this scenario, it would be wise to install a drain pan.

It is an inexpensive way to make sure that if your water heater does leak, then the water shouldn’t damage the room or any of your belongings.

This is really important for any rooms that a water heater is placed into that contain live electrical outlets, or electronics in general.

Even just a small leak could destroy all your electronics and create a fire. 

Buying The Right Water Heater Pan

If you decide you want to purchase a water heater drain pan, then there are a couple of things you need to be aware of.

You want to pick the right size and the best material for your pan. 

Below, we have put together a short guide on what you need to look for when choosing your water heater pan. 


The majority of drain pans are made from either steel, plastic, or aluminum.

There may be other materials available, yet these three are known to be the most durable materials that you should choose from.

Out of the three materials we have just mentioned, plastic is the most temperamental.

This is due to a lower quality manufacturing process, and temperature changes can cause the plastic pans to crack. This then means you can’t use the pan.

Compared with a pan made out of steel, which is extremely durable. Steel is definitely the most durable material that can be used to make your drain pan from.

However, due to their high durability, they are much more expensive. Yet, this price balances out the fact they will last you a lot longer and have to be replaced much less. 

Finally, we have drain pans made from aluminum. It has to be said that aluminum is just as durable as steel. However, it is also much cheaper than a steel pan.

Therefore, this is a common and popular choice for the majority of people. 


You need to make sure that the size of your drain pan is correct.

This can seem like a scary process, however to work out the right size that you need, we have this simple step-by-step guide for you to follow.


You need to work out how wide your water heater is. To do this, you need to place your measuring tape on one of the top edges of your water heater.

Then measure the distance to the edge opposite. 

Pan Width Choice

With the width of your water heater measure, now you can start looking for a drain pan.

The rule is that your drain pan for your water heater needs to be a minimum of 2 inches wider than the width of your water heater. 

For example, if your water heater is around 30 inches wide. Then you want to purchase a water heater drain pan that is a minimum of 32 inches wide. 

Depth Decision

With the width all sorted, you can now turn your attention to the depth of the drain pan.

You may assume that a really deep pan will be better for you. However, this isn’t always necessarily true. 

This is because these pans are designed to stop water damage that is caused by steady and slow leaks.

However, if your water heater (see also ‘Water Heater Hissing? Do This Immediately!‘) is leaking large quantities that a shallow drain pan can’t cope with, then you will find yourself suffering with lots of water damage.

Also, if your water heater is leaking too much, then there could be a problem with your water heater that you need to see to and get repaired.

As your water heater shouldn’t be leaking large quantities. 

Also, the pipes that are connected to your drain pan will only be able to handle a certain amount of liquid at once.

If your pan is too deep, this will delay this process. Also, if your water heater starts leaking a lot more, then this could cause flooding and water damage to your home. 

Installing Drain Pans Under An Existing Water Heater

Installing Drain Pans Under An Existing Water Heater

Normally, when it comes to installing a drain pan, a professional is hired to do the job. This is because they have years of experience and know what they’re doing.

Yet, it is possible for anyone to install a drain pan, which can also save yourself a lot of money. 

If you want to install your drain pan yourself, then our guide below will take you through every step


Step 1 

Turn off the water supply leading from and to your water heater. You can disconnect them as well if you wish to. 

Step 2 

Next, for a gas water heater, disconnect the service line which is attached to the water heater. For an electric system, you need to switch off the main power supply. 

Step 3 

Now it is time to drain the water from your tank. You can do this by opening the temperature and pressure valve.

Don’t try to move the tank before you have drained all the water from it. Water inside the tank makes it extremely heavy, thus heavy to lift. 

Step 4 

Once all the water has been drained from the tank, find someone else to help you lift the water heater. 

Step 5 

Lift the water heater and place your drain directly underneath it. You want to make sure that you point the discharge hole in the same direction that the drainage pipe will be. 

Step 6 

Set the water heater down inside the drain pan. Then reattach the water lines. 

Step 7 

Close the drain valve and the temperature and pressure valve.

Step 8 

In case anything leaks, place paper towels on all of your connections. 

Step 9 

Now you can reconnect your supply lines. For a gas system, you will need to relight the burner.

With an electric water heater, you need to turn the main power supply on.

Step 10 

Finally attach the drain pan discharge hole to the drainage pipe.

The pipe will drain the water away from the pan, so that it doesn’t build up and overflow, causing water damage. 

As you can see, it isn’t difficult to install a water heater drain pan yourself. It is also important that you take good care of your water heater (see also ‘Wood Burning Water Heaters | How It Works, Types, Buying Tips‘).

This is down to regular maintenance checks. If you don’t look after your water heater, then over time the quality will begin to falter and leaks may begin to arise. 

Then your drain pan may not be able to cope if it begins to leak too much.

This could then cause flooding and damage to property, which is what you’re trying to avoid by installing a drain pan in the first place. 


In the majority of scenarios, you need a drain pan under your water heater. They help to prevent flooding and damages to your home. 

We hope you have found this article useful and now understand if you need a drain pan under your water heater.

Don’t forget to read our guide on what to look out for when purchasing your drain pan. 

Thanks for reading!

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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