Thursday, June 8, 2023


Can I leave the RV’s water heater on electric all the time when plugged into shore power?

Dear Dave,
My RV’s water heater uses both LP and electric. Can I leave the electric on all the time to heat water when connected to shore power? Thank you. —Ben, 2003 Monaco Knight

Dear Ben,
The short answer is yes; however, here is the longer answer. From what I see in most of the RV Trader and other used listings, your water heater is a 10-gallon electric/LP model.

When you leave the water heater on it will continue to “cycle,” which is heating the water to a certain temperature, typically 120 degrees, shutting off until the temperature drops about 15-20 degrees, then starting back up to heat it again. This happens all day and night, so it does put an additional strain on the heating element as it operates on resistance and basically “glows” hot, which means it would wear out faster.

Don’t let water heater turn on without water in it

The main issue, in my opinion, is risking the unit turning on without water in the tank. If you run the unit without water in the tank, the heating element will get too hot and burn out within a few minutes and could cause other damage to the unit. Since it only takes about 10 minutes or less for a water heater to get to operating temperature, it seems to me it wouldn’t be that much of an inconvenience to turn it on and off.

The heating element itself is not that expensive, and you can find them on Amazon here.

The issue is the labor to get to it and what other damage to the unit might happen. Sometimes it takes out the entire water heater.

Clean the tank out a couple times a year

I have done this on propane models quite often. What I found was the water seemed to get a little skanky with all the temperature changes. Keep in mind that you are typically using hard water that has a lot of calcium, lime, rust, and other minerals. If you do decide to leave it on all the time, I would recommend cleaning the tank out a couple times a year. Use a water heater wand to get the 2” of scum that settles on the bottom and doesn’t flow out with simple gravity when draining. Find one on Amazon here.

If the RV’s water heater is a Suburban model, it will have an anode rod that is part of the drain plug. This rod acts as a sacrificial metal for the minerals in the water to attack and deteriorate. It’s not a huge issue; however, leaving water in the tank continually and leaving it on will “cycle” the water from hot to cold to hot. That continual chemical reaction will deteriorate the anode rod faster.

 You might also enjoy this from Dave 

Why does RV’s water heater work on LP but not on 120 volts?

Dear Dave,
Regarding my RV’s water heater, the gas part works good after I replaced the disc thermostats but I cannot get the electric to work right. It’s an Atwood 10-gallon unit. I have replaced the solenoid switch and the heating element, but it’s still not working. —Brad, 2006 Monaco Monarch

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here


We have a popular forum for Ask Dave. Please be as brief as possible. Attach a photo or two if it might help Dave with his response. Click to visit Dave’s forum. Or send your inquiries to him using the form below.

Click or drag a file to this area to upload.



Dave Solberg
Dave Solberg
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.


4.8 9 votes
Article Rating
Subscribe to comments
Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments
1 month ago

About leaving the electric water heater on all the time. The problem isn’t leaving the water heater on, when there is water present, it’s leaving your water on when you are away. I’m a full timer and I can’t tell you how many rigs I’ve seen with water pouring out of their slideouts, because they had a water leak while they were gone. ALWAYS shut your water off while you’re gone, even if you think it’ll be only a few minutes. Trust me…..

1 month ago

Same question as yesterday!

Neal Davis
1 month ago

Thank you, Dave!

martin a
1 month ago

Embarrassing tip once when preparing for a trip after de winterizing. I was testing the WH on propane and it wouldn’t fire up. I was getting frustrated, then remembered I had turned on the electric element earlier. Of course the propane would not come on the water was already hot DUH!

Last edited 1 month ago by martin a
1 month ago

We have always turned off our water heater after we are done with showers and washing dishes. No need for it to be on all day, and especially if we leave for a day trip.

1 month ago

Also, if your water heater is an automatic electric – propane, if the power fails it will continue heating with expensive propane. This could happen when you are at work, away or in the middle of the nite. Possible fire hazard with an unattended appliance?

1 month ago

We cycle the hot water heater on before we need it. The fast heating cycle works with a little thought and planning.

Bob M
1 month ago

With the price of electricity going up, it don’t pay to leave the hot water heater on until needed.

Tom H.
1 month ago

That RV WH tank rinser looks like a game changer. It seems it’s a much better tool than the basic plastic wand I use. I will be ordering one before my anode inspection later this season. Thanks for sharing Dave.

Tommy Molnar
1 month ago
Reply to  Tom H.

I agree, Tom. I’ve never seen a cleaning wand this fancy. Wifey just looked it up on Amazon (of course) and found it for $11.99. The cheapo wand we’ve been using shows at $10.19!. The accompanying video shows how there are two different spray patterns as well. As soon as we get home we’ll be ordering this fancy schmancy wand.

1 month ago
Reply to  Tom H.

I have one and PLEASE be careful as the wand on Camco model can pop off with too much water pressure. It works great, but I ALWAYS hold onto the wand as you do not wanting it shooting off into your water tank!

Tommy Molnar
1 month ago
Reply to  Leonard

Do you mean the tip will blow off? And if that’s the case, what do you hold to prevent the tip from coming loose?

Sign up for the

RVtravel Newsletter

Sign up and receive 3 FREE RV Checklists: Set-Up, Take-Down and Packing List.