Tuesday, November 28, 2023


Ask Dave: At what temp should I be worried about exposed water lines freezing?

Dear Dave,
We have a 2017 Jayco 30X class C RV. We love our rig and keep it extremely well-maintained as we travel 8-9 months out of the year. We are occasionally caught in cold weather, but we try our best to avoid temperatures from 25 degrees F or lower. Our rig has heating elements in the holding tanks but we do have some exposed water lines underneath the RV. When temperatures are cold, we open cabinets at night. I have mounted a light fixture in the plumbing bay that I wired directly to our panel box. During cold weather, I turn the light on and I have a remote temperature monitor so I can see the temperature in the plumbing bay.

Question: What are typical low temperatures a rig like ours can handle without freezing damage to lines? In addition, would it be reasonable to insulate the water lines under our rig to make our RV more of a four-season RV? Many thanks for your advice. We love your forums. —Greg

Dear Greg,
I have not done any specific research on freezing temps, but have camped many times in below-freezing weather and even once in Fargo, ND, where it was -20 F. Yes, I did freeze some of the water lines, even with a basement model that supposedly had a heated basement and service compartment for year-round use. When I got back to Winnebago the product engineer stated: “We heat the basement, but not to keep it from freezing.” Wow! He later became the President and CEO.

Even though I don’t know specific temperatures, I would suggest taking precautions any time temperatures get to or below the freezing mark as a slight wind could enhance the freezing effect, especially with exposed water lines underneath the RV.

Every year here in Clear Lake, IA, there is a winter dance party celebrating the music of the ’50s. Since there are no “green rooms” for performers in the building, we use RVs parked outside. In February the temperatures can get brutally cold! All systems, including the plumbing, need to be functional for the performers. So we take extra precautions to keep everything from freezing. Any exposed water lines get wrapped with heat tape. I recently came across one from Pirit, which also makes a heated freshwater supply hose. You can find the pipe heating cable on Amazon.

These come in lengths up to 30’ and with Pex lines are easy to wrap. In your case, I would suggest wrapping the lines and then also installing an insulating pipe foam such as this.

You can use the foam tubes or “noodles” like these, or a roll of wrap-around insulation. One of the owners that loaned us their RV liked the setup so well he had us permanently install the tape with the insulation. We then covered it all with a corrugated plastic tube used for sump pumps to protect everything. That was nice, as we did not have to go through the work every winter during the event.

Other protective measures for water lines

Other protective measures we use are heating pads in the service center, as it is typically exposed to some harsh, cold winds. We also found that skirting the underside was a big help, as well. Since we are from Iowa, of course, we use straw bales, but there are several methods from skirting to products like AirSkirts™, which help to block wind from getting underneath the rig.

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.

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Dave Solberg
Dave Solberghttp://www.rv-seminars.com/
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.



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Joe (@guest_163106)
1 year ago

We have a heated basement but only if using the aqua-hot for heating. Many times the electric fireplace and a small space heater on a dedicated circuit works for us down to about 25-20 degrees. With that in mind I installed electric heat tape and foam insulation on all of my water lines. Inside the wet bay and at the water tank/water pump area I installed a couple of 100 watt, 120 volt cartridge heaters on a stand-off using a thermostat set to come on at about 40 degrees inside the compartment. It was a pain to get at all of the piping and meant carefully removing a lot of the inside wood, trim, cabinets washing machine and such to get to everything. We have endured some really cold weather and I never lose any sleep worrying about things freezing up.

Richard (@guest_163090)
1 year ago

Our ’05 Holiday Rambler has a belly pan around the tanks, but it is not “4 Season” equipped. I have found it will stay thawed if temps drop as much as 25° for less than an hour. Outside that window I have to help it with heaters or light fixtures. I also ran a furnace duct into the wet bay.

Richard (@guest_163088)
1 year ago

16 yrs FT – I have found MOST RV manufacturing “Officials” to be incompetent, liars, or both, and really don’t care.

Bob M (@guest_163087)
1 year ago

Thats why the quality of Rv’s are so poor. They have brain dead engineers they make CEO’s and bosses. My employer did the same.

Bob Palin (@guest_163084)
1 year ago

My totally anecdotal rule of thumb is that I am safe if it is not going to be below 28F for more than a couple of hours and the daytime temperature will reach 60F. Your mileage may vary…

(This is with no heating, my furnace is broken and I don’t have shore power)

Last edited 1 year ago by Bob Palin
Drew (@guest_163077)
1 year ago

Generally speaking- temps at or below freezing for a few hours shouldn’t hurt anything. I used to waste my time and money by winterizing.

Kyle Petree (@guest_163074)
1 year ago

I looked up your rig, and based on that am surprised to hear that it has exposed water lines. Are you sure about that? Maybe what you are seeing is a propane line?

With a rig like that I wouldn’t worry about going down to 10F or so without special precautions. Of course – your input water hose being the exception and it should be insulated or disconnected and drained.

Below around 10F for extended periods, well, every rig is different on how well it will bear these temps and I would be looking for a forum or group online that have the same make/model for guidance on their individual experiences.

Kenneth Fuller (@guest_163100)
1 year ago
Reply to  Kyle Petree

They are exposed on the Class C Jayco’s. I had a 2013 Greyhawk 31FK and currently have a 2019 Greyhawk 29MV. A water line froze last winter in Texas during the “big freeze” they had. The temperature was consistently below freezing for approximately 5 days in the mid 20’s. I insulated every exposed line that I could find. We just endured freezing again in Florida (23 degrees) with no problems.
Greg, I would insulate every exposed pipe you can find if your using the coach in sub-freezing weather. It gives a good peace of mind.

Kyle Petree (@guest_163101)
1 year ago
Reply to  Kenneth Fuller

Interesting. Definitely something to look at at know. I should have asked if there was an insulated and heated underbelly on that model.

Thank you Kenneth.

Ron T. (@guest_163052)
1 year ago

We finally visited the Clear Lake Ballroom, an impressive place, last summer. I’ve been a big fan of Buddy Holley for decades. Did my museum graduate work in Lubbock which has some related artifacts & visited his grave outside of town. Now live in Appleton, WI where he played before playing Green Bay that evening before going to Iowa. The Ballroom in Green Bay also celebrates every year with a tribute band.

volnavy007 (@guest_163030)
1 year ago

If wind had no effect on the temperature of the water in pipes vehicular radiators wouldn’t work and manufacturers would save money by not installing fans to create air currents for those radiators.

Paul (@guest_163069)
1 year ago
Reply to  volnavy007

The fans work because they circulate the air through the radiator, taking the hot air away and leaving ambient air that is much cooler than the radiator fins, allowing the radiator fins to transfer heat to the cooler air. But the fan does not lower the temp of the ambient air.
As for using hay bales for skirting, they are very effective in blocking air from circulating under the trailer. They are a long time favorite in the Great Plains area for mobile homes, but not so much anymore due to being extremely flammable … I understand many insurance companies now prohibit using bales with rigs they insure.

TIM MCRAE (@guest_163024)
1 year ago

Wind does not ‘enhance the freezing effect’.!!

Sure, wind can blow warm air under your trailer away, obviously, but it is the ambient temperature that causes freezing, not the amount of wind.

Wind has no amplifying effect on inanimate objects like pipes & water. Don’t confuse this with wind chill {which only effects living things}.

Skirting or straw bales help because you are insulating and keeping the area under your RV warmer, hopefully at a higher temp than it is being cooled by the outside temp.

Given time everything is going to reach the ambient temp regardless of wind, unless you add heat. Heated compartments or the heated RV interior radiate some heat. Hopefully enough.

Larry Lee (@guest_163037)
1 year ago
Reply to  TIM MCRAE

Tim, you are correct but only because you inserted the phrase “given time”. Given enough time even insulation becomes irrelevant. Wind speeds up the rate of thermal conduction. Blocking the wind makes it take longer to freeze the water solid to the point of expansion and pipe bursting. That allows your RV pipes to survive below freezing temperature provided it is only a few hours duration and not too many degrees below freezing AND no wind.

Bob p (@guest_163023)
1 year ago

You can ask any “expert” weather guesser and they’ll tell you that wind chill factor has no affect on anything but exposed skin. Lol but we all know of instances where exposed water lines or containers of water froze where the temperature was only 32 but the wind chill was in the low 20s. If you’re connected to city water you could let you faucets “drip”. That would also protect the parks water line. Of course that’s not practical if you’re boondocking.

Bob P (@guest_262857)
16 hours ago
Reply to  Bob p

At the school system I worked in in AL we had a representative from PEX water lines visit us promoting his product. He had a 3’ long piece of PEX that was frozen solid with no evidence of a leak, the line was expanded to at least 2” in diameter, impressive! The secret to this demonstration was the stainless steel fittings on the tubing, they don’t break unlike the plastic fittings in your RV. Manufacturers use cheap plastic fittings that will break when frozen.

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