How To Drain an RV Hot Water Heater (Why and How Often)

One of the many duties that have to be done from time to time is draining the water heater. But when you are new, you may not know how to do this simple task. That is okay, everyone has to learn how to do it eventually. You just need the right tools.

The first step is to get prepared. You may need a bucket to capture the water. You also need the right tool. For a Suburban, you will need a water heater wrench or a 1 1/16 socket to get the plug out. Other brands may take smaller or larger sizes of sockets.

To learn more about draining your water heater tank, just continue reading our article. It provides the information you want to know about so you can do this task like an experienced RVer. The reading of this article and the task do not take a long time to do.

Do I Need To Drain My RV Hot Water Heater?


Yes, you should but it is not as often as you might think. There are some important reasons why you should drain your water heater and when you should do this.

The first reason is that sitting water will develop a foul odor. Your water heater and plumbing may start to get that sulfur, rotten egg smell to them when the water sits for too long inside the tank.

To avoid that odor, just remember to regularly drain the tank and refill it with fresh water. Another reason you need to drain the tank is cold weather. If you leave the tank and plumbing full of water over the winter it can freeze.

Water expands when frozen and when it does, it will break the tank, water lines, seals, and more. One owner did not winterize his RV and he had to pay $8000 in repairs the following spring.

To avoid costly repairs, make sure to drain that tank when you are not using it for a long time. When you are using your RV, you do not have to drain the tank as the water does not sit inside the tank for longer than a day or two.

How Often To Drain The RV Hot Water Tank

This depends on how often you use your RV or travel trailer. If you do not use it over the winter, make sure to drain all the water out of the tank and all water lines, and the water pump. Then you need to winterize those same parts to make sure nothing gets frozen or broken.

If you are a part-time RV family, then you drain the water tank if the RV or trailer will sit unused for at least 2 weeks or more. This helps protect you from getting that sulfur smell.

Some people say to drain it after every use and this is a good option as well. That way you know it has been done and it does not take long to refill the water tank.

Or you can choose your own schedule even if you are a full-timer. Emptying the water tank from time to time helps rid it of any bacteria or germs that may have found their way inside.

Who Can Drain a Water Heater?


Just about anyone can. This should not be a warranty voiding activity so you should be able to handle the task yourself. That is as long as you have the proper tool to pull the plug.

The age of the person doing this task does not have to be that old either. Young boys, teenagers, or young adults can all handle this task. Whoever does it, just has to be careful about where they are dumping the water.

If you do not want to do this task, you can take your RV or trailer to a professional mechanic who will do it for you. This option is not recommended as it will cost you more than you may want to pay.

When you or someone in your family does this chore, make sure to let the water cool first. You do not want to have anyone get burnt by hot water. Just be cautious and there is no need to overdo it when it comes to safety precautions.

How To Drain The RV Hot Water Heater

You may think that all you have to do is go outside, lift the panel and remove the plug to drain your water heater. That is a simplified version of how to drain an RV water heater. There are a few more steps involved in this process.

Step 1: Turn off the power to the heater. Whether it is gas or electric models, make sure the power is off before going further

Step 2: Turn off the water supply to your RV. Then open your faucets to relieve any pressure.

Step 3: Wait for the water to cool. This may take some time so be patient and have a back up task ready while you wait.

Step 4: Remove the drain plug. Suburban water heaters need a 1 1/16ths inch socket while the Dometic/Atwood brands need only a 1/2 inch socket. Be careful as these plugs may be made of nylon.

You do not want to strip their heads or threads. Use 6-point sockets if you can as the 12-point options may do the stripping for you.

Step 5: Open the pressure relief valve. This will supply some air pressure to help drain your water tank

Step 6: Use a water tank rinser to flush the tank out. It will connect to a regular garden hose.

Step 7: Once all the water is out of the tank, reverse your steps to fill it up again and seal the tank. Make sure the faucets are off, the water pump is on and that water is flowing nicely through your system again

Step 8: Check for any leaks just in case something went wrong during this process. Don’t forget to close that pressure relief valve.

Where is the RV water heater drain?

This is not hard to find. The good news is that it is in a very accessible part of your water tank and RV. Getting to the drain plug and removing it does not take a lot of time.

The first step is to go outside your RV or trailer and locate the exterior panel. Then simply remove the panel and this might be held in place by a few screws or bolts.

Once you have the panel off, you should see the drain plug on the bottom of the exterior of the water heater. All you have to do is reach in and twist the drain plug off and the water should start flowing out.

You open the pressure relief valve to aid in draining your water tank. The incoming air will help push the water out and get the tank nice and empty. In this situation, RV makers did not mess up and they kept this location nice and simple.

Tips For Draining The Hot Water Heater in RV


The biggest tip that can be given for this chore, is about the heat of the water. You must shut the power off and you must wait till the water is cool. Any other option is not acceptable and puts you or a family member at risk of injury.

While this may take an hour or so, that will give you plenty of time to do other items on your honey-do list. Another good tip is never to put any chemicals down your drains while the water is hot and the system is pressurized.

If you do, you may experience a nice explosion or other chemical reaction that causes a lot of damage to your RV, etc. That explosion may also harm you or your family so avoid this situation at all costs.

A third tip would be to check to see if you can drain your water heater through the low point valve. While some RV models may allow this option, others will not. You just have to check on a case-by-case basis to see if this is possible or not.

How do I Get Sediment Out Of My RV Water Heater?

The cause of this sediment is the aluminum anode rods you may be using. They are famous for creating sediment in RV water heaters and from time to time you will have to clean out your tank.

There are different methods you can use but they all start with draining your water tank first. You can’t clean the sediment until you get the water out. After the tank has cooled and is empty, hook up your shop vac.

There should be an adapter that will fit your water tank so hook it up if you have it and get ready to vacuum.

When the shop vac is ready, insert it into your water heater and start cleaning out the sediment. The reason you do this is one, that this sediment takes up valuable water space.

The more sediment you have, the less water in the tank. RV tanks are small enough as it is. Before you do the vacuuming, you should hook up a water wand that can flush out the tank.

The power of the wand will clear out a majority of the sediment for you. Then the vacuum will remove what is left. To avoid sediment build-up, just replace your aluminum anode rods with magnesium ones.

About the only brand, you would have to do this replacement is with Suburban. Atwood/Dometic does not use anode rods anymore.

Can't Drain The Water Heater


There are a few simple problems that cause this situation to take place. One is that there is a clog somewhere in the tank that needs to be removed. That clog usually takes place around the drain plug. Just clean out the clog and the water should flow again.

Generally, you should not have this problem unless the sediment has built up so high removing the drain plug doesn’t do anything. Or there may be a problem with the shut-off valve.

If the ball valve inside of this part is broken then the water tank will not drain. This is a situation where you can only replace the broken part. Then you may find a problem with the venting of the water heater.

If that is clogged or the pressure relief valve does not open, the water should not drain out. You have to unclog the vent system or replace the pressure relief valve to get the water tank back to normal.

Finally, make sure you are opening the water heater drain valve. This is a simple mistake as some people try opening the low point drain or the cold water line drain by mistake.

Not All Water Heaters Are The Same

Dometic/ Atwood has changed the design of their RV water heaters. Instead of using anode rods, they have put in liners to protect the water heater interior construction.

This design has removed the possibility of sediment and you may not have to flush the tank out unless it has sat for too long without being used. Only the Suburban RV water heaters use anode rods.

You do have to flush and clean those water tanks on a regular basis.

Some Final Words

Draining your water tank is easy. All you have to do is follow those few simple steps and the job is done. The key is to make sure you turn off what you turned on, plugged what you have opened, open what you have plugged, and so on.

Also, make sure to be patient and wait for the water to cool off. Being safe is always a good attitude to have when working around appliances that heat up to high temperatures.

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