Water expands when it freezes. When that expansion happens inside your RV's plumbing — pipes, fittings, water pump, water heater, faucets, and holding tanks — things crack, split, and burst. The repair bill from a single freeze event can easily exceed $1,000, and the water damage that follows when everything thaws can total the interior of an RV. Winterizing prevents all of this, and the supplies cost under $30.

If you store your RV in any climate where temperatures drop below 32°F (0°C), you need to winterize. Even if temperatures only occasionally dip below freezing overnight, a single hard freeze is all it takes.

What You Need

Method 1: RV Antifreeze (Most Common)

Antifreeze Winterization

  1. Drain the freshwater tank. Open the tank drain valve (usually underneath the RV) and let the tank empty completely.
  2. Drain the water heater. Turn off the water heater and let it cool completely — never drain a hot water heater. Remove the drain plug (and the pressure relief valve for full drainage). Let all water drain out. Leave the plug out for now.
  3. Open all faucets and drain lines. Turn on both hot and cold at every faucet, the shower, and the outdoor shower (if equipped). Open the low-point drain valves — most RVs have two or three (usually color-coded blue for cold and red for hot). This empties the plumbing lines.
  4. Bypass the water heater. Engage the bypass valve(s) so antifreeze flows directly through the plumbing without filling the 6-gallon water heater tank — this saves 6 gallons of antifreeze. Most modern RVs have a bypass kit pre-installed near the water heater.
  5. Close all faucets and drain valves. Everything needs to be closed before you pump antifreeze through the system.
  6. Connect antifreeze to the water pump. Most RVs have a winterization inlet — a tube near the water pump that you can detach from the freshwater tank and drop into a jug of antifreeze. Alternatively, use a hand pump or an external winterization kit. Turn on the water pump.
  7. Open each faucet one at a time (hot and cold separately) until antifreeze (pink) flows from the faucet. Then close it and move to the next one. Do the shower, the outdoor shower, and the toilet. Run antifreeze until it flows pink from every water outlet.
  8. Pour antifreeze down each drain. About a cup down each sink drain, the shower drain, and the toilet to fill the P-traps. This prevents the trap water from freezing and allows sewer gas to pass through blocked (frozen) traps.
  9. Reinstall the water heater drain plug. Replace the cap on the RV sewer outlet. Close everything up.

Method 2: Compressed Air Blowout

An alternative (or complement) to antifreeze. Use an air compressor with an RV blowout plug to push water out of the plumbing lines using compressed air. Never exceed 45 PSI — higher pressure can damage RV plumbing fittings.

Drain all tanks and the water heater as above. Connect the blowout plug to the city water inlet. Open each faucet one at a time until water stops sputtering and only air comes out. Work through every faucet, hot and cold, plus the shower and toilet.

The compressed air method removes water without introducing antifreeze, which means a cleaner de-winterization in spring. However, it may not clear every low spot in the plumbing — which is why many RVers combine both methods: air blowout first to remove the bulk of the water, then a small amount of antifreeze in the low points and P-traps for belt-and-suspenders protection.

Don't forget these. The water heater is the most commonly forgotten component — leaving it full of water guarantees freeze damage. Ice maker lines, outdoor showers, washing machine hookups (if equipped), and water filter housings also need to be drained or blown out. If your RV has a whole-house water filter, remove the cartridge and drain the housing.

Beyond Plumbing: The Full Winter Storage Checklist

Batteries: Disconnect house batteries or connect a battery maintainer/trickle charger. A fully discharged battery can freeze; a fully charged battery is protected to well below -40°F. If storing without a maintainer, check the charge monthly and top off as needed.

Propane: Turn off the propane supply at the tank. Close all propane appliance valves. Leave the fridge door open (propped with a towel) to prevent mold and odor.

Tires: Inflate to the maximum sidewall rating. If parked for months, tire covers block UV degradation. If possible, move the RV slightly every few weeks to prevent flat spots.

Seals and roof: Inspect all exterior seals — around windows, doors, vents, and the roof. Repair any gaps or cracks before winter. Water intrusion during storage causes more long-term damage than anything else.

Pest prevention: Close all exterior openings — furnace vents, water heater vents, fridge vents, plumbing access panels. Mice can enter through gaps as small as a dime. Steel wool in openings and peppermint oil sachets inside help deter rodents.

Interior: Remove all food, open all cabinets and drawers (for air circulation), and place moisture absorbers to prevent mold. Leave roof vents cracked slightly for ventilation if climate allows.

De-Winterizing in Spring

Reverse the process: disengage the water heater bypass, close all low-point drains, reconnect the water pump to the freshwater tank, fill the tank with fresh water, and run every faucet until the antifreeze (pink water) is completely flushed. The water heater drain plug goes back in before you fill it. Run the system for several minutes to ensure all antifreeze is purged. Then sanitize the freshwater system with a bleach solution (quarter-cup per 15 gallons) to clear any residual antifreeze and bacteria.

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For the full sanitization procedure and year-round water system care, see our Complete Guide to RV Water & Sanitation.