What Size Is an RV Water Heater Drain Plug? (Atwood, Dometic)

When you like doing your own maintenance work on your RV or travel trailer, it is always good to know the sizes of nuts, bolts, and plug heads. That way you can reach for the right tool and get the task done quickly.

The ratchet size is one of the more important sizes to know when removing your drain plug. For Atwood and Dometic, you will need a 7/8 or 15/16ths inch socket to remove the plug. For Suburban, you will need a 1 1/16th inch socket to get the job done.

To learn more about these sizes just continue to read our article. It has the information you need to know so you can get your maintenance work done quickly. Take a few minutes to see how this important information helps you.

RV Water Heater Drain Plug Size


The drain plug size will differ between the brands. One brand will make theirs larger than their competitors while the competitors may go smaller. The smaller size fits into your toolbox easier and does not take up to much space.

There is a difference between thread size and head size. The latter is the size that you need to fit with a socket and it is always going to be larger than the thread size. In most cases, you will be looking for a drain plug that has a 1/2 inch thread size.

For head size, the socket is not going to be the same between Dometic, Atwood, and Suburban. That means you will have to change sockets if you change water heater brands. We will get to those sizes shortly.

The most important size you need to worry about when it comes to drain plugs is their thread size. If that is too large or small, then you have to make another trip back to the store to get the right one. Size does matter when it comes to appliances and repairs.

Dometic Water Heater Drain Plug Size


Some people thought that Dometic did not make water heaters but they do. They have the drain plugs to prove it. With this brand, you will need a plug that has a 1/2 inch MPT (thread size) to fit their water heaters.

The socket size you will need has to be 15/16ths to fit the head. The tricky part about Dometic drain plugs is that they are made from glorified plastic. These nylon plugs can easily be damaged and you have to be very careful when taking them out and putting them back in.

The last thing you want to do is separate the plug head from the threads. The extra work is frustrating and not worth the time. It is a good thing that more than one comes in a package, just in case you do make a mistake.

Atwood RV Water Heater Plug Size


This company is owned by Dometic and you would think that the two companies would use the same size parts. They do for the thread size as this drain plug is supposed to be 1/2 inch. But the head or socket size is roughly 7/8ths.

Keep in mind that the measurements given here are for a 6-gallon water heater and the larger tanks may have larger drain plugs. Check your manual to make sure. You can get a Camco brand drain plug that should fit all three brands.

If you can, you may pay a little less than if you bought the brand-name plugs. Do not be surprised if all these brands have switched to nylon construction materials, so be careful when removing and installing these plugs.

Suburban RV Water Heater Drain Plug Size


Thread size should be the same for this brand as well. But double-check as we have seen some reports that there may be a 3/4 inch size. The head size would require a socket measuring 1 1/16 to get the plug out of its spot.

You can find these plugs just about anywhere RV supplies or plumbing supplies are sold. You may want to consider upgrading to a metal or brass plug. That way you do not have to worry about damaging them.

Plus, the metal may cost more, but it last longer. You can talk to a plumber about this upgrade and see which way is the best way for you to go.

The Tools You Need

Now that you know the size of the tool you need, you should know that there are a variety of tools you can use. Of course, the first one would be a socket and a socket wrench. These come in handy and you can always get an extension if you have a tight fit.

But not everyone has a socket set and when you don’t you can use either a crescent wrench or an adjustable wrench (not the same tool). These wrenches come in the exact same sizes as the sockets do with the adjustable option more flexible and can be used for larger or smaller nuts and bolts.

Finally, someone has made a dual-headed RV water heater wrench. This tool comes with both the 7.8 and 15.16 sizes needed for many water heaters. It is a handy little tool as it is bent into a shape that makes them perfect for working drain plugs.

Oh and do not forget the Teflon tape. This is an essential tool to have when putting the plug back into its spot.

Some Final Words

Knowing the right sizes makes your maintenance work a lot easier. You can get those plugs on and off quickly giving you more time for more important duties. Always make sure you have the right tool for the job as that will help as well.

For drain plugs, you have a good assortment of tool options to use. They are not expensive either.

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