Keeping RV water lines from freezing during cold winter use

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Dear Gary,
We have a Class C motorhome. We have used it quite often this winter and have resisted winterizing it because we use the shower and toilet and such. I have heated it through the winter so far without any problems, but during a recent cold snap the bathroom plumbing froze. I believe the problem is where the water lines run under the floor to the opposite side of the cabin. Interior heat, I suspect, was not enough to keep the lines from freezing under the floor.

To thaw the lines, I am using a bullet heater under the motorhome outside to try and get the floor temperature above 32 degrees. In the living area I have added a ceramic heater and fan and have opened all the drawers to get heat back into the recesses of the bathroom. So far I have been able to unfreeze the hot water line, but not the cold water line yet. What can I do to keep this from happening again? I cannot find any diagrams telling me exactly where the water lines run under the coach. Is my only solution to winterize those lines? —David

Dear David,
Winter RVing is indeed enjoyable — especially if the family is into the snow toys and/or slope activities. But, as you say, it can be difficult if the plumbing succumbs to below-freezing temps.

snowI would be surprised if the water lines truly are routed via the exterior under the coach. Typically they will route in and through cabinets or in voids through the walls and maybe under the top flooring. Some coaches, however, are better insulated than others, so it could be an insulation issue. If you can trace the lines, it may be possible to wrap them each in foam-type insulated jacket available at most home supply centers. There is also heat tape that can be wrapped around them in those areas prone to freezing. Accessibility is the key, however.

If you didn’t need water for the shower, another option would be to blow the fresh water lines clear of all moisture and simply use bottled water for flushing the toilet.

Also remember, running water is less likely to freeze. If possible, when you are connected to a dump assembly in a campground, for instance, leave the gray tank valve open and the cold water seeping just a little through the bathroom faucet. The gray water will continually drain and this will minimize the chances of the cold line freezing. All this advice from a guy who spent all but the last few years living in Florida and Southern California! But it may help. Other than that, winterization is the only other viable option when the coach is not in use.

gary-736

 

Read more from Gary Bunzer at the RVdoctor.com. See Gary’s videos about RV repair and maintenance.

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Richard Schroeder

Living in MN we have been winterizing our class A motorhome each winter. However, now we are considering spending part of the winter in the south so I need some advice.
If the RV is winterized (no water in the tanks), do we drive it south until we reach warm enough temperatures to drain out the antifreeze in the lines and then add water?
And what about on the return trip if MN still has freezing temperatures when we return? Drain the water before we drive home again? Thanks

Peggy Phillips

When I was going south for just February, I winterized my class A and used gallon bottles of tap water from home to flush the toilet and for drinking. I drained the antifreeze when I arrived in south Texas, and used the city water connection. I didn’t fill my water tank. I winterized before leaving for home at the end of February, and used the gallon water jugs for the return trip. Now, since I’ve retired, I just leave MN at the end of October and plan my return so its warm enough for the pipes not to freeze!

theresa brown

Our class C did the crazy last year when we neglected to do a basic winterize – end result – spring rolled around and we went to turn the water on and the kitchen faucet literally blew right off the top of the sink – turns out, not only did the lines freeze but it also damaged the water pressure regulator – after replacing sink faucet and pressure regulator, we also found the lines sprung a leak at the shower area so we finally had to take in the RV for the nice rv repair folks down the road to… Read more »

James

Identical problem, simple solution. If temps are below freezing operate from your freshwater tank but do not leave the on-demand water pump energized. When needed to flush a toilet etc, turn the pump on, use the water, turn the pump off and drain the waterlines from faucet furthest from the pump (ie:kitchen hot water faucet) and leave the faucet open. Water can’t freeze if line is empty! With next use, turn pump on first, then shut off the faucet to expell air. If any ice has formed from remnant of moisture in the line, the slightly warmer freshwater from the… Read more »

Bob C.

Re: RVDoctor suggestion to leave water running to prevent freezing lines. That can work in a house but not in an RV. Under below freezing conditions, the “running” water will freeze in the stinky slinky and plug it in no time.

Alpenliter

Like Barry, I too used the slow trickle method with the same results. The rear kitchen sink drained the length of the trailer. The long expanse of drain line was exposed and froze, filling the line, the galley gray tank, backed up to the sink, then onto the kitchen and living room. Stepping barefoot into freezing cold water at 3am was not a good way to start my day. So before using the trickle method, trace where that water will go!

Warmonk

We spent four winters in our Outdoor RV Timber Ridge (one of the Nash family – as is Arctic Fox). One winter saw temperatures down to minus-22 C/minus-8 F (yep, we’re Canadian and were in Canada). That same winter brought six weeks of continuous below freezing weather – day and night. Just so you know, we did not put skirting around the trailer and did not use RV anti-freeze. We were the only rig in the park that did not have humidity problems – like water running down the inside walls or freezing on the inside of the windows. We… Read more »

Barry

I used the faucet drip method once. Gray valve was open and drain hose was in sewer pipe.
Drain hose froze solid, backed up water into the gray tank and overflowed the shower.
Took a couple of days below freezing, but not the best long term solution.

Al Wegleitner

I have used a 60watt Flood light installed in a cheap metal flexible desk lamp that I place in the fresh water tank bay and leave plugged in while we are hooked up – works well and have not had any frozen pipes or water tank/ pump issues down to -30 F so far.

Gregory Illes

With the aid of Winnebago’s excellent chassis drawings, I identified where the water lines are routed. I then installed a low-draw circulation fan to flow a small amount of air from the cabin, through the inner walls and floor spaces.

Now, using the efficient catalytic heater, I keep the cabin at 45-50F or so, and the circulation fan keeps the air in the ducts from getting below freezing. This solution even works when boondocking.

Randy Hoepfl

Gary,
We solved the freezing problem by adding a hybrid electric heating system called the Cheap Heat system. With this system we can heat our RV all year by keeping it plugged in.