Freezing weather can damage an RV water system in a single night. Proper winterization protects the pump, water heater, faucets, toilet, tanks, outside shower, and every low point in the plumbing.
Before you begin
- Use only non-toxic RV/marine antifreeze intended for potable-water systems.
- Check the RV manufacturer’s instructions for model-specific valves, appliances, and drain locations.
- Never put automotive antifreeze into an RV freshwater system.
1. Drain the freshwater system
Turn off the water heater and allow it to cool. Disconnect city water, switch off the water pump, open the freshwater-tank drain, and open hot and cold faucets to relieve pressure. Open all low-point drains and drain the water heater according to its manufacturer’s procedure.
2. Bypass the water heater
Set the water-heater bypass valves so antifreeze does not fill the heater tank. Confirm the valve arrangement for your RV before continuing.
3. Protect filters and appliances
Remove inline or canister water-filter cartridges and install the proper bypass plug or empty housing. Follow the winterization instructions for ice makers, washing machines, dishwashers, tankless heaters, and other water-connected appliances.
4. Blow out the lines or pump antifreeze
If using compressed air, use an RV blowout adapter and keep pressure within the RV manufacturer’s limit. Work one fixture at a time until water stops. If pumping antifreeze, use the pump winterization tube or approved setup, then open each hot and cold fixture until pink antifreeze appears.
5. Do not miss hidden fixtures
- Kitchen and bathroom faucets
- Shower and outside shower
- Toilet valve and sprayer
- Low-point drains
- City-water inlet
- Black-tank flush connection, when applicable
6. Protect traps and tanks
Pour enough RV antifreeze into each sink and shower drain to protect the P-traps. Add antifreeze to the toilet bowl and holding tanks as recommended for your RV.
Final check
Label the water heater as bypassed, confirm drains and valves are in their intended storage positions, and keep a written checklist for spring recommissioning. When temperatures return, flush the system thoroughly and sanitize the freshwater system before use.
Related RV water-system products
Preparing the rest of your freshwater setup too? Browse RV Water Systems, including our 2-Stage RV Water Filtration System and 16,000 Grain Portable RV Water Softener. Always follow each product’s separate winterization instructions.