RV Water Heater Drain Plug Size: Everything you need to know


Whether you carry out the maintenance job of your RV or not, knowing the correct dimensions of the components is always crucial. Because at the time of replacing or buying, you would need to know the right size of those parts. Some of those parts require regular replacement and a water heater drain plug is one of them.

But what is the accurate size of the water heater drain plug? Drain plugs come in various sizes; the most relevant is 15/16″.  Brands set the dimensions to have an advantage over their competitors and can go either smaller or bigger.

In this article, I’ll be telling you about the optimum drain plug size for your water heater. Therefore, let’s check it out.


What is an RV Water Heater Drain Plug? 

The drain plug in the RV water heater is one of the two essential components of the water heater. It plays a big part in draining the water from the RV water heater and the drain. 

You would mostly find different brands offering a water heater drain plug kit, which includes all the components for making everything fully functional. Moreover, the size of this component is essential, and you’ll get to know the reasons in the section below.

What is the Optimum Size For an RV Water Heater Drain Plug?

As I mentioned earlier, different brands have different offerings in terms of size for the drain plug. In this regard, your main challenge is finding the most appropriate option for your RV water heater. 

The biggest problem I faced while testing the plugs of different sizes was that the bigger plugs seemed too big. On the other hand, the smaller drain plug had issues plugging the drain out of the RV water heater.

I tried the 15/16” drain plug, again the most common of all sizes available. You’ll also find other dimensions like the 13/16” and 7/8“ along with plenty of alternatives. 

Before all this, you must know what head and thread sizes are. Head size and thread size should always differ, with the former being bigger in size. For the drain plug, I recommend looking for ½ inch thread size.

Read Also: How to Troubleshoot & Fix RV Tankless Water Heater Problems?

Water Heater Drain Plug Sizes of Renowned RVs

The dimensions for water heaters differ from RV to RV. That said, the drain plug sizes for the water heaters are also variable. The drain plug sizes of some of the common RVs are discussed below:

RV BrandPlug Size (Thread)
Dometic½ inch
Atwood½ inch
Forest RiverVariable
Suburban½ or ¾ inch

1. Dometic RV

Most people are unaware that Dometic makes water heaters for RVs. That said, they also come with drain plugs, and their water heaters require plugs with ½ inch thread size.

In addition, you’ll need a socket with the dimension 15/16″ to fit well with the head. However, these drain plugs are vulnerable and prone to damage when installed or removed.

2. Atwood RV 

For this company, ½” is the size for the drain plug. Still, the socket size you will need is ⅞”, which is quite different from the other brands. 

While installing the drain plugs from this brand, you should properly check the manuals and see whether the plug is larger than it’s supposed to be. In addition, drain plugs from this brand come with nylon materials. Therefore, you should be cautious in their installation and removal.

3. Forest River 

Drain plug size entirely depends on the water heater model. It can be either ½” or ⅞’ drain plug. Also, since 15/16” are common, chances are high that the plug size can be that also.

4. Suburban RV 

For the Suburban RV water heaters, the drain plugs are widely available compared to the other ones. It depends on the model type, where 7/8 “ or 15/16” might be more suitable.

Read Also: Where is the RV Water Heater Reset Button and How To Use It?

How to Replace the RV Water Heater Drain Plug?

Most of the time, the drain plug in the water heater is the most neglected component. That eventually prompts the need for replacement because not changing the plug might result in no scope for taking the plug out. The outcome will be a constant water leak.

But I found the replacement process pretty straightforward. Let me tell you the steps to perform in the option below:

Step 1: Arrange the Tools

The first step would be to gather all the necessary tools for replacement. It will include the new drain plug, wrench, extension tape, and a bucket to avoid water spills.

Step 2: Take Out the Old Plug 

In this step, you need to use the wrench and remove the old water heater drain plug. You should unscrew the plug appropriately, and the water doesn’t spill very severely.

Step 3: Install New Plug 

Screw the new water heater drain plug into the drain’s opening generally with your hand. After this, you may use the wrench to tighten the plug so that water pressure doesn’t affect it.

Step 4: Seal with Extension Tape

No matter which type of plugs you install, there is always a chance of leaks. As a precaution, use extended tape to seal the drain completely. You can do this by measuring the dimensions around the plug and wrapping the tape around.

Read Also: Why Does My Rv Water Heater Sound Like A Jet Engine?


Many queries will be stirring in your mind regarding the water heater drain plug. Some of the prominent ones are listed below:

Can you use a brass drain plug in the RV water heater?

Yes, it is possible to use a brass drain plug in the RV water heater. In this regard, the water heater has to accept ½” fitting to accommodate the drain plug, and there will be no issues with the plug being made of brass.

How to know what size drain plug I have?

To understand the accurate size of the drain plug, you’ll need to figure out the diameter of the drain mesh. Apart from this, you can also measure the underside of the existing plug. Eventually, you’ll get to know the size required.

Is using an old drain plug a good idea?

Drain plugs wear down over time, so continuous usage of the same drain plug is something I won’t recommend. Therefore, using an old drain plug isn’t the best idea.

How often should the RV anode rod be replaced?

You should replace the anode rod in the RV every 1-3 years. You should check the anode rod on intervals and determine whether it got rusted. Signs of corrosion mean the rod requires replacements.

Read Also: 7 Easy Solutions For RV Water Heater Igniter Not Clicking

Final Thoughts

The drain plug in the RV water heater is susceptible to wearing out when you use it for a long time. It’s a common phenomenon; you must replace it before it gets too late. 

But before replacement, you must ensure that the drain plug size goes well with the water heater model in your RV. Usually, 15/16” is what you’ll get the most, but while selecting other sizes, check the thread size requirements.

Moreover, the water heater drain plug with an accurate size for the heater model is essential as it will affect the procedures of the component.

Read Also: Why Is The Dometic RV Water Heater Not Working On Electric?

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