De-winterizing checklist

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How do you dewinterize an RV?

Close it up, put the water heater back in the loop, fill, flush, look for leaks and sanitize, and only then switch the heater on. Most of the list can go in any order; the water heater's part can't. It has to be back in the loop (bypass at normal) and full of water, proven by a hot tap running without spitting air, before anything switches it on, because an electric element switched on without water around it burns out. Turning the bypass back before the flush, as the checklist does, means the hot-side flush fills the tank and proves it full in the same pass, so the order itself protects the element. The checklist above is built around those two rules and adds the steps your rig needs: a tankless heater skips the bypass entirely, a rig that was blown out has no pink to flush, and a motorhome gets the chassis where a trailer gets the breakaway switch. The fall half, with the antifreeze your rig takes, is on the winterize calculator.

How long do you run the water to get the antifreeze out?

Less than you'd think for the lines, more than you'd think in total. A 28 ft trailer's supply lines hold 0.8 gallons, and the pump clears that in seconds. What takes the water is running every tap until it's clear and a little beyond, filling the heater's tank, and flushing the toilet until the bowl is clean. With each side of each fixture run 15 seconds to clear and 30 more past clear, at a typical pump's 3 gallons a minute:

Heater bypassed in the fall. Lines: 3 ft of ½" PEX per foot of rig. Antifreeze coming out = what the winterize calculator puts in for the same rig. Taps: every fixture's hot and cold side at (15 + 30) s × 3 gpm, plus 3 toilet flushes per bath. "Start with" adds 5 gal so the pump never runs dry; on a van with a 20-something-gallon tank, fill it and top up partway through. 3 gpm is a pump's open-flow rating, so the taps figure is a ceiling.

"Until it's clear" means until it stops foaming and the pink tint is gone. A faint sweet taste can stay longer: a trace of propylene glycol lingers in a carbon filter's housing and in the heater's tank, and the sanitizing rinse that comes next takes the last of it. If the antifreeze went into the fresh tank instead of the lines, drain the tank before you start: the pickup sits above the bottom, and the pink underneath it would be the first thing the pump pulls.

Where does the antifreeze go when you flush it?

Down the drains and into your gray and black tanks. Every drop that went into the lines in the fall comes out of a faucet or the toilet. That's where it should go. RV antifreeze is propylene glycol, low in toxicity, but a holding tank's contents belong at a dump station, not on the ground at a storage lot, so dump on the way to the first campsite and add water and treatment to the black tank after. If you flushed with the gray valve open onto the ground, you poured the same glycol there directly.

When can you turn the RV water heater back on?

Switch it on once a hot tap has run steadily and the sanitizing rinse is done. While the tank's open, look at what's in the drain hole. A Suburban heater has a steel tank protected by a magnesium or aluminum anode rod that dissolves instead of the tank; Suburban says to replace it once it's about 75% consumed, and spring, with the heater drained, is the time to look. An Atwood or Dometic heater has an aluminum tank, a plastic drain plug and no anode; don't add one. The water heater calculator works out showers per tank and recovery once it's running. Either way, wrap the threads in fresh plumber's tape, close the relief valve, and check for drips once the tank is hot.

What else needs checking when you take an RV out of storage?

The water is the part everyone remembers. The rest of the list is what goes wrong on the first trip:

• Propane. Open the valve slowly and brush soapy water on every joint from the cylinder to the regulator and beyond; a leak shows as bubbles in seconds. Light the stove first to push air out of the line, then the other appliances.
• The alarms. Press test on the propane, CO and smoke alarms, and read the date printed on each one. The common Safe-T-Alert propane/CO units are to be replaced no later than five years after the production date on the back; other makers print their own limit. An alarm past that date is replaced.
• Batteries. A lead-acid bank that sat without a maintainer may have sulfated; charge it fully and check the water in flooded cells before counting on it.
• Tires. Cold pressure to the weight label, and the four-digit date code on every sidewall. Trailer tires age out on the calendar, whatever the tread looks like.
• The roof and the rodents. Sealant around every vent and the air conditioner, and a look under the sinks and at the furnace intake for nests and chewed wire.

The checklist above carries all of these, in the order you'll reach them walking around the rig.

When should you dewinterize?

After the last hard freeze, not the first warm weekend. A line inside the floor survives a light frost, but the outdoor shower, the low-point drains and an exposed pump freeze first, and a plumbing system full of water in a late cold snap splits the same fittings antifreeze was protecting. If a warm spell tempts you early, flush and sanitize, then keep the furnace on or blow the lines out again before the next hard freeze. The water you put in will need somewhere to go too: the Boondocking Days page counts how long the fresh tank lasts once you're camping.