How to De-Winterize Your RV

De-winterizing is the reverse of winterizing — you're flushing out all the antifreeze, checking the system for damage from the winter, sanitizing the fresh water tank, and confirming everything works before your first trip. It takes 1–2 hours and should be done before you need the water system, not the morning you're leaving.

Step 1: Reinstall the Water Heater Bypass

If you used the antifreeze method for winterizing, your water heater was bypassed so antifreeze didn't fill it. Switch the bypass valves back to their normal "flow-through" position before you start filling the system. Your owner's manual shows the valve positions — typically the bypass routes water around the heater, and normal operation routes water through it.

Also reinstall the water heater's anode rod and close the drain petcock if you opened those during winterizing. Reinstall any inline water filters you removed (use new filter cartridges — old ones shouldn't be reused after sitting dry all winter).

Step 2: Connect Fresh Water and Flush All Fixtures

Connect to a hose bib or fill your fresh water tank. Don't start the water pump yet — use city water pressure or gravity from a full fresh tank. This way if there's a leak, you're not running the pump against a damaged line.

Open each faucet one at a time — hot and cold — and let water run until it flows completely clear with no pink tint from the antifreeze. Work through every fixture:

1. Kitchen sink (hot, then cold)
2. Bathroom sink (hot, then cold)
3. Shower (hot, then cold)
4. Toilet — flush several times
5. Outdoor shower (if equipped)
6. Icemaker line (if equipped)
7. Washing machine connection (if equipped)

Step 3: Check for Leaks

While water is running through the system, walk through and inspect every visible fitting, supply line, and connection. Water damage from a burst fitting discovered after your first trip is far more expensive than catching it now. Pay attention to:

• Under-sink supply lines and drain connections
• The toilet supply valve and base seal
• Water heater inlet and outlet fittings
• Any fittings you can see in exterior access bays
• The water pump inlet and outlet connections

Once you've done the gravity-fed test, switch on the water pump and pressurize the system from the fresh tank. Let the pump run until it cycles off (system is pressurized), then turn the pump off and watch the pressure gauge or listen for the pump cycling. If the pump kicks back on within a few minutes without any faucet open, you have a slow leak somewhere.

Step 4: Sanitize the Fresh Water Tank

Even with a good winterizing job, a tank that has sat for months should be sanitized before use. This is also a good time to make it a seasonal habit — sanitize in spring and fall.

The full process is in our complete sanitizing guide. The quick version:

1. Drain the fresh tank completely
2. Add 1/4 cup unscented bleach per 15 gallons of tank capacity, diluted in 1 gallon of water
3. Fill the tank completely with fresh water
4. Run all faucets until you smell bleach at each one
5. Let sit 4 hours minimum (overnight is fine)
6. Drain completely, refill with fresh water, flush all fixtures until bleach smell is gone

Step 5: Test the Water Heater

Before lighting the water heater, confirm it's fully filled with water — a dry-fire will damage the heating element. With the bypass in normal position and the system pressurized, open the pressure relief valve briefly to confirm water (not air) comes out. Once you're confident it's full, light the pilot or switch on the electric element per your heater's instructions.

Check around the water heater door and external access panel for any signs of animal nesting — mice love the insulated water heater compartment for winter housing. Clear any debris before firing the heater.

Spring De-Winterize Checklist