How to de-winterize your RV: a step-by-step spring guide

De-winterizing an RV means flushing out the antifreeze, refilling and restarting the water system, and sanitizing it so the rig is safe to use again after winter storage. It is winterizing in reverse, and done in the right order it takes under an hour and sends you into the season with water you would happily fill a glass from.

If you winterized properly in the fall, your plumbing is full of pink RV antifreeze and a few things are drained or bypassed. Spring is about undoing all of that carefully, then sanitizing the fresh water system so months of sitting have not left it stale or growing something. Rush it and you can dry-fire your water heater or drink last year’s antifreeze. Follow the steps below and neither happens.

What you will need

Very little, and most of it you already have from the fall. The only consumables are water, a little bleach, and a fresh filter cartridge.

• A drinking-water-safe hose: a potable (white or blue) hose, not a regular garden hose, for filling the fresh tank.
• Plain unscented household bleach: for sanitizing the fresh water system. Avoid scented, splashless, or color-safe versions.
• A replacement water filter cartridge: install a fresh one after sanitizing, not before.
• A funnel and rubber gloves: for measuring and pouring the bleach solution.
• Basic hand tools: a socket or wrench for the water heater drain plug or anode rod.

How to de-winterize your RV, step by step

Work through these in order. The sequence matters most around the water heater, where doing things out of order is what damages the element. Give yourself about an hour.

1. Inspect the rig first Before you touch the plumbing, walk around. Check the roof and window seals for cracks, look for signs of pests or water intrusion, check the tires for pressure and cracking, and look under the rig for anything that came loose over winter. Better to find a problem now than on the highway.
2. Reconnect and check the battery Reinstall the battery (or reconnect it), make sure it is fully charged, and check the terminals for corrosion. A battery that sat all winter may need a full charge before it will hold.
3. Reinstall the water heater plug and close the drains Put back the water heater drain plug or anode rod you removed in the fall (replace the anode rod if it is more than half gone), and close all the low-point drain valves. The system needs to be sealed before you add water.
4. Take the water heater out of bypass Turn the bypass valves back to the normal position so water will flow through the water heater again. Leave the heater itself switched off for now.
5. Leave the water filter out Do not install a new filter cartridge yet. You are about to run antifreeze and then bleach through the lines, and neither should pass through a filter. It goes in last.
6. Fill the fresh water tank and flush out the antifreeze Fill the fresh tank with potable water, turn on the water pump, and open each faucet, hot and cold, one at a time until the water runs clear instead of pink. Do every fixture: kitchen, bathroom, shower, outside shower, and the toilet. Keep flushing until there is no pink and no antifreeze smell anywhere. (If you blew your lines out with air in the fall and used little antifreeze, this goes quickly.)
7. Fill the water heater before you power it This is the one that damages rigs. With the heater out of bypass, open a hot-water faucet and let it run until water flows out in a steady stream with no sputtering. That tells you the water heater tank has filled. Only then turn the water heater on. Powering an empty water heater dry-fires and can ruin the heating element or the tank.
8. Check for leaks With the system pressurized, look under every sink, around the water pump, at the water heater, and at the toilet for drips. Winter can loosen a fitting. Catch it now, dry, not later on a wet cabinet floor.

Sanitize the fresh water system

Water that sat in your tank and lines for months should be sanitized before you drink or cook with it. It is quick, and it is the step that makes your water genuinely safe rather than just clear.

1. Drain the flushing water Empty the fresh tank and the lines you just flushed so you start the sanitizing with an empty system.
2. Mix the bleach solution Use one quarter cup of plain unscented household bleach for every 16 gallons your fresh tank holds (about one ounce per 8 gallons). A 40-gallon tank needs roughly half a cup. Dilute it in a gallon of water first, then pour it into the fresh tank through the inlet with a funnel.
3. Fill and circulate Fill the tank the rest of the way with potable water, turn on the pump, and open every faucet, hot and cold, until you smell bleach at each one. That confirms the solution has reached the whole system.
4. Let it sit Leave the solution in the tank and lines for 12 hours, and no more than 24. Longer than a day and the bleach can start to degrade rubber seals.
5. Drain and flush clean Drain the whole system, refill with fresh water, and run it through every faucet until the bleach smell is completely gone. This usually takes a couple of fill-and-flush cycles. Do not use the water until the smell is gone.
6. Install the fresh water filter Now, with clean sanitized lines, put in a new filter cartridge. Installing it last means it filters your drinking water instead of the antifreeze and bleach you were flushing.

Finish the spring check

With the water system live and clean, wake up the rest of the rig so nothing surprises you on the first trip. Twenty minutes here prevents most roadside headaches.

1. Turn the propane back on and test appliances Open the propane valves, check the connections for leaks with soapy water (watch for bubbles), and light off the stove, furnace, water heater, and refrigerator to confirm each one runs.
2. Test the safety devices Check the smoke, carbon monoxide, and propane detectors and replace batteries, and confirm your fire extinguisher is charged and in date. These sit unused all winter, so never assume they still work.
3. Check the tires Inflate to the pressure on the sidewall or your rig’s label, inspect for cracking or flat spots from sitting, and check the age. Tires that look fine can still be too old to trust.
4. Test the electrical system Connect to shore power, check that the lights, outlets, GFCI, slide-outs, and awning all work, and make sure the converter is charging the battery.
5. For motorhomes, check the drivetrain Look at the engine oil, coolant, and belts, start the engine and the generator, and if the rig sat a long time or is due, have a mechanic look it over before a big trip.

Common de-winterizing mistakes to avoid

Each of these is easy to sidestep once you know it, and each one causes a real spring headache.

• Powering the water heater before it is full: the fastest way to kill the element. Confirm a steady hot-water stream first.
• Installing the water filter too early: it should go in after flushing and sanitizing, not before.
• Skipping the sanitize step: clear water is not the same as clean water after months of sitting.
• Leaving bleach in longer than a day: it can damage seals. Twelve hours is plenty.
• De-winterizing too early: a late hard freeze on freshly filled lines undoes all your fall work.
• Forgetting to test the safety detectors: smoke, CO, and propane alarms are the one thing you cannot afford to have failed silently over winter.

The bottom line

De-winterizing is a calm, ordered hour: inspect the rig, reconnect the battery, reinstall the water heater plug and take it out of bypass, flush every line until the pink is gone, fill the water heater before you power it, sanitize the fresh water system with a little bleach, and finish with a fresh filter and a check of propane, tires, and safety devices. Do it in that order and your rig is ready for the season, with water you can trust.

Planning ahead for next fall? Here is the other half of the season: how to winterize your RV. For everything in between, see our RV maintenance guides.