How to Winterize an RV in Utah
Water expands when it freezes, and a closed water line has nowhere to let it go. That is the entire reason winterizing exists, and it is why many owners put RV antifreeze in their plumbing before a Utah off season. Water freezes at 32 F whether your camper is in a driveway in Millcreek, a storage lot in Spanish Fork, or parked up a canyon. The fix is simple and an owner can do it. Here is the order, and the parts people forget.
Why leftover water is the thing that breaks parts
Draining by gravity leaves water behind in low spots and fittings, and that leftover water can freeze and split a line. The ice pushes outward, the fitting or the plastic gives, and you do not find out until spring when you turn the pump on and water comes out of a cabinet.
Our service department has written up about 4,200 winterizing jobs since January 2023, and about 70 repair orders in that same stretch were freeze damage. Faucets lead the list at about 20, water lines are close behind at about 18, then the water pump, the water heater and plain old fittings at about 8 each, toilets at about 7 and outdoor showers at about 6. Notice how many of those are fixtures and fittings that hold a little water after draining. A cracked water heater coil means a new water heater. A split water pump body means a new pump.
Utah makes this sneaky. Higher canyon and mountain spots can get much colder overnight than the valley; Peter Sinks, near Logan Canyon, recorded -69.3°F in 1985, which is Utah's record low (about -69°F when rounded). The earlier state record was -50°F at Woodruff in 1899. Spring and fall swing the same way.
One more thing worth knowing up front. A unit that arrives at our shop already frozen cannot be winterized until it is thawed, and that thaw time goes on the repair order as a frozen fee. Doing it before the cold settles in is always the easier path.
Winterizing with RV antifreeze, in order
This is the method our winterizing notes name most often (about 1,160 jobs since 2023), and it is the one most owners can repeat at home. Use RV antifreeze only, the kind labeled for potable water systems. Automotive antifreeze is not safe in RV water lines, is not rated for drinking water plumbing, and should never go anywhere near your fresh system.
Start by draining everything that holds water, including the low point drain lines. They are usually a pair of colored pipe ends hanging under the floor, one hot and one cold. Let them run until they stop.
Next, drain the water heater. Make sure it is off, cool, and not under pressure before you pull the drain plug or anode rod. Opening the pressure relief lever helps it empty. Once it is dry, set the bypass valves so antifreeze goes around the tank instead of into it. Skipping the bypass fills the water heater tank with antifreeze, so you use a lot more of it. Our notes mention the water heater bypass on about 610 jobs.
Close the drains, then feed antifreeze into the pump. Many units have a siphon hose and valve at the pump; if yours doesn't, a pump bypass/converter kit lets you draw straight from the jug. Turn the pump on and open one fixture at a time, hot side then cold side, until the pink color runs steady. Kitchen faucet, bathroom faucet, shower head, toilet valve and sprayer, outdoor shower, exterior kitchen if your floorplan has one.
Finish inside the drains. Pour enough antifreeze down each sink and shower drain to fill the P trap, and pour some into the toilet bowl so the bowl seal and the line into the black tank stay protected. Turn the pump off. Check your owner's manual for whether the city water inlet check valve needs clearing on your unit. When you finish, set the faucets the way your owner's manual says; Keystone, for example, says to set the water heater bypass valve to the winterize position. Remove the water filter cartridge and drain the filter housing (or use a bypass tube).
Blowing the lines out with air
The other common method is an air compressor and a blow out plug at the city water inlet. Drain everything the same way described above, bypass the water heater the same way, then push air through and open each fixture one at a time until only air comes out. Work hot and cold separately. Our shop notes show the air method on about 170 jobs, so it is less common than antifreeze, but it works when it is done patiently.
Two cautions. Set the regulator to the pressure your owner's manual specifies (many manufacturers say no more than 30 psi) and no higher; the goal is steady airflow, not force. And air alone does not protect your drain traps or your toilet.
The spots almost everybody misses
The outdoor shower is often overlooked. It sits in an exterior compartment, it has its own hot and cold lines, and people forget it exists until it is dripping pink or, worse, dripping clear in March. Run both sides until antifreeze (or only air) comes out, then set the handles the way your owner's manual says.
The toilet is next. The toilet valve and its supply line hold water, so hold the valve open until air or antifreeze comes through. Open the low point drains to empty the lines, then close them before antifreeze goes in, or the antifreeze runs out onto the ground.
If your unit has an ice maker or a washer, those have supply lines and valves that need to be handled the way the appliance manual says, often with a dedicated shutoff and drain. The same goes for an exterior kitchen faucet, a filtered drinking faucet, or a tankless water heater, which has its own procedure. We have replaced a grey tank hose that broke after it froze.
Tanks, storage and the manual that outranks this article
The tanks are the volume you are emptying before any of this starts, and they vary by floorplan.
| Tank | Most of the new travel trailers on our lot run from |
|---|---|
| Fresh water capacity | 26 to 60 gallons |
| Grey water capacity | 27 to 70 gallons |
| Black water capacity | 26 to 49 gallons |
Get the tanks empty, then set the dump valves the way your owner's manual says for storage. Check your HOA rules, city ordinance and storage lot rules before you plan around a cover or a running furnace; Utah law limits HOA restrictions on driveway parking for ordinary vehicles, but it does not cover motor homes or RV trailers.
Your owner's manual is the authority for your specific unit. Bypass valve locations, water heater type, low point drain placement and appliance procedures all change from brand to brand and year to year. If the manual contradicts anything here, follow the manual. If you would rather hand it off, our service department does this work, and October and November are our busiest winterizing months, so book early.
Frequently asked questions
Can I use automotive antifreeze in my RV water lines?
No. Automotive antifreeze is not safe in RV water lines and does not belong in a potable water system under any circumstances. Use only RV antifreeze that is labeled for drinking water plumbing.
If I blow the lines out with air, do I still need antifreeze?
Yes, for the drain traps and the toilet. Air clears supply lines, but your P traps are designed to hold standing water and the toilet bowl seal needs liquid to stay sealed. Pour antifreeze into every sink and shower drain and into the bowl after the air work is done.
What happens if my RV already froze before I winterized it?
It has to be thawed before anyone can winterize it. Our repair orders add a frozen fee for the thaw time, and if something split you are looking at a repair on top of the winterizing.
Can I still use the trailer for a winter trip after it is winterized?
You can. Since January 2023 our shop has written about 4,200 winterizing jobs and about 1,700 de-winterizing jobs, so both sides of that cycle are routine work for us. Some owners skip the plumbing entirely on a short cold-weather trip and bring jugs of water instead.
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