RV Water Heater Maintenance

Ahhhh the glamping life!

Enjoying a hot shower after a day of hiking or swimming is the new normal. You can take the comforts of home with you in your house on wheels. Given this “luxury” of today’s RV’s, here’s a little information on how to maintain your RV water heater so it continues to provide hot water for years to come.

In “techie” terms it’s called a “Water Heater” and not a “Hot Water Heater”. If you think about it, if it was hot water…well you wouldn’t have to heat it, now would you?

The typical tank style RV water heater comes from Atwood/Dometic or Suburban.

Both of these units require regular maintenance to ensure it performs optimally and you can continue to take hot showers and wash your dishes. There are other types of RV water heaters, such as “on demand” but this article is specifically for the tank style.

RV Water Heater Maintenance Basics

RV Water Heaters

In the typical bumper-pull or 5^th wheel travel trailer RV, a tank style water heater is installed to provide hot water using either 120v AC electric and/or propane. I say “and/or” because you can use both electric and propane to quickly heat the water for things like showers, where using both will heat the water quicker than using either individually.

If you are at a campground that has full hook-ups, most campers will use the electric method to provide hot water. If you are boon docking then propane is an on-board option. Did you know that in either case the 12v DC coming from the battery is still a necessity? You see the “brains” of your RV appliances require 12v DC to run their control boards. This holds true for absorption (gas/electric) RV refrigerators, RV air-conditioners, and some other RV appliances.

RV Water Heater Maintenance

But what about performing routine maintenance on your water heater?

If you have a Suburban or Atwood/Dometic RV water heater you will need to perform the procedures below to ensure the water heater operates efficiently for a long time.

One of the differences between the Suburban RV water heaters and Atwood/Dometic RV water heaters is the “plug” that you remove to perform the tank draining procedure or the use of the anode rod.

Anode Rods

A Suburban RV water heater has a steel tank, from 4 to 16 gallons, which is prone to deteriorating, so it requires what is known as a sacrificial anode rod. The Anode rod is called “sacrificial” because as water is used in the tank, and fresh water fills the tank, the rod will start to deteriorate instead of the tank through a process called “electrolysis”. This is normal and what the rod is there for.

So, part of the procedure is simply observing the condition of that anode rod to determine when to replace it. Replacement anode rods can be purchased at your local RV dealer parts department as well as Amazon. They are an inexpensive way to protect the Suburban RV water heater, and are part of the routine maintenance plan.

Drain Plugs

Atwood/Dometic water heater tanks are made out of aluminum and do NOT require the anode rod.

Instead if you do have an Atwood/Dometic RV water heater you want to ensure you keep or replace the drain plug with the original style plastic plug. If you put an anode rod into an Atwood/Dometic water heater you risk the threads of the rod, where it screws into the tank, fusing together and later removal can be quite a task.

Stick with the plastic plug. Just do it.

How to Maintain You RV Water Heater

Parts and tools needed:

For Suburban water heaters, have a spare anode rod ready in case you need it. For Atwood/Dometic have a spare plastic plug.
1- 1/16^th socket to remove the Suburban anode rod or 7/8” or 15/16” socket (it could be either) to remove the Atwood/Dometic plastic plug.
Plumbers Teflon tape, usually white in color
Coleman water heater flush wand or something similar. Pictured is the Coleman version with water shutoff on the handle which makes it very convenient.

Bucket or something to catch the water (optional)
Soft clothes/towels
CLR cleaner or similar calcium cleaner

Ok, all that said here is the procedure to follow:

Turn off the water heater source
- If you are using the water heater PROPANE option, turn the propane switch off from inside the RV
- If you using the water heater ELECTRIC option:
  - The Suburban water heater electric switch is outside your RV on the water heater itself
  - The Atwood/Dometic electric switch is typically on the same switch panel as the propane switch.

Once you have removed the heating source, run your kitchen faucet until no more hot water is coming out. Since you turned off the heating source, the cold water entering the tank is not being heated so it shouldn’t take long for the “hot” water to come out cold.
Turn off the water to the RV.
- Close the valve at the campsite pedestal
- Or, if you are using water from your fresh water tank, turn off the water pump.
Open the kitchen sink faucet again on the hot side and the cold side to relieve the water pressure. Some water will come out until the pressure is stabilized. Leave them open until the procedure is completed. If you have a single lever kitchen faucet, open it in the “middle” position.
Locate the anode rod or plastic drain plug at the bottom of either the Suburban or Atwood/Dometic water heater.

NOTE: The Atwood/Dometic plastic plug may be blocked by the propane inlet, and the plug may need to be removed with an adjustable wrench or specific wrench made to do this. If you are uncomfortable doing this procedure, contact a certified RV technician to perform this procedure.

CAUTION: Make sure that water coming from the sink was cool before attempting this next step. If you do NOT ensure it was flowing cool at the faucet you could risk serious injury of scalding.

Suburban only – remove the anode rod and examine it for deterioration. It should look similar to rock candy on a stick. If it looks like a July 4^th sparkler then it’s time to replace it. Photo shows a worn anode rod on the left and a brand new anode rod on the right. Somewhere in between is acceptable. It doesn’t have to be brand new, but you don’t want it to be just the thin metal rod.

Atwood/Dometic only – remove the plastic plug and set aside
At this point water will be draining out of the tanks and getting all over the side of the RV below it. There isn’t much you can do about this so just let it drain. You might be surprised how much water is in the tank! Look at a 5 gallon typical bucket from the hardware store – if your tank is 10 gallons it’ll fill two of those! Bet you didn’t think there was THAT much water in there!

NOTE: You might want to perform this procedure as part of your camp breakdown procedure before leaving a campground. If you think about it, 10 gallons of water x 8.2lbs per gallon = 82 pounds! Why carry the extra weight of that water while towing the RV?

CAUTION: It might seem tempting to open the pressure relief valve to drain the tank faster. The open faucet in the kitchen will provide the relief to allow the tank to drain. If you open the pressure relief valve it may leak afterwards.

Once the tank is empty, you need to flush the tank out. You can close the kitchen sink faucet and turn the water on to the RV, but a better way is to use the wand mentioned above. You attach it to the end of a hose and it includes a water shutoff on the handle.

CAUTION: Only turn this wand ON when it’s already inserted into the tank or you will get the “water cobra” as the wand’s high pressure spray will bend the tip, like a cobra ready to strike, and spray water all over the place. Not that I’ve tried this myself. LOL

- Once the wand is inside the tank “rake” it from back to front. By turning the hose you should be able to aim the spray inside to flush all 360 degrees of inside the tank. While performing this “tank flush” you might see some white chunks flowing out of the drain. This is calcium build up and you want to remove this. Regularly performing this flushing should reduce the amount that comes out, but if you let this go too long don’t be surprised if you see a LOT of calcium chunks. The most important part of this flushing is to ensure you’ve removed, or flushed, as much of the sediment from the bottom of the tank so make sure that nozzle is pointed down while you rake it. What I do first is the raking procedure with the wand, then when I’ve gotten it to the point that mostly clear water is draining out, turn off the wand and turn on the water to the RV which floods the tank again, then turn off the water supply again and finally let it drain completely.

Suburban only – after assessing the anode rod condition, replace or reuse the existing one. Place Teflon tape on the threads of the rod, and carefully insert it back into the threads being careful not to cross-thread it. It’s a lengthy rod and the weight inside does make it a challenge to thread it properly. Tighten it but do not over torque it.

Atwood/Dometic – replace the plastic plug. You can also use Teflon tape here to ensure a snug fit. Don’t over-tighten it. The last thing you want is to break the plastic plug and have to try to remove it.
If you haven’t already, close the kitchen faucet, and any other faucets inside. You can now turn the water back on to the RV. You should hear the water tank filling. DO NOT open that pressure relief valve. This is especially important NOT to do at this time. The water heaters are meant to have an air pocket at the top and opening that pressure relief valve removes that air pocket.

Once the tank is filled you can turn on the heating source again, electric and/or propane.

Note: It’s wise not to keep both electric and propane on unless you have high demand, like multiple showers in a row. There is no need to waste propane if you are connected to campsite power.

CAUTION: One of the quickest ways to break your water heater’s electric element is to turn it on before there is water in the tank. It only takes a couple seconds for that element to be destroyed if there is no water in the tank. As a standard practice, make sure the tank is full by turning on the hot water on your kitchen faucet until water runs from it. Make yourself a note when you arrive at a campsite to do this before turning on the electric on your water heater.

Note: Don’t forget to turn OFF the electric element when you break camp and move the RV. This should be part of your camp breakdown procedure.

RV Water Heater Maintenance

That should do it for your water heater routine maintenance.

If you perform this procedure at the end of each camping trip, for the part-timers, or once every three months, for the full-timers, your water heater should perform well for years to come. If this, or other routine maintenance, is “above your pay grade” then I highly suggest hiring a certified RV technician to do the procedure. Water heaters, A/C units, and other RV specific appliances need routine maintenance and an RV tech is highly familiar with the procedures.

See my other routine maintenance procedures to learn how to winterize your RV’s water system. It’s important to know where and how to use your water heater bypass valves to perform that procedure.

Enjoy your camping adventures!

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