Winterizing an RV or camper

The water system is the highest-priority winterization task and the most common source of expensive freeze damage. A cracked fitting or pipe discovered at spring startup can cost more to repair than an entire season of storage fees.

• Method 1, compressed air blow-out: Attach an air compressor (regulated to 30-50 PSI, do not exceed this) to the city water inlet. Open each fixture in sequence, farthest from the inlet first, and blow through until only air exits. Do low-pressure side and high-pressure side separately if your system has a bypass. Blow out the water heater inlet line with the bypass valve open. Do not blow the toilet through; the valve seal can be damaged by direct air pressure. Blow-out does not completely dry P-traps or the toilet bowl, these still need RV antifreeze poured in.

• Method 2, RV antifreeze via pump switching: This is the most thorough method for ensuring every line is protected. Start by bypassing the water heater, most RVs have a dedicated winterization bypass (one, two, or three valves depending on the system; check your owner's manual and label each valve). Bypassing is essential, or you will waste several gallons of antifreeze filling the 6-10 gallon heater tank before any antifreeze reaches the rest of the system. Once bypassed, locate the fresh water pump's inlet, on most RVs there is a short hose running from the fresh water tank to the pump inlet. Disconnect that hose and insert it into a jug of RV antifreeze (propylene glycol, the pink kind). Switch on the pump. Open each fixture one at a time starting with the farthest from the pump, faucet cold, then hot, then the next fixture. Run until pink flows steadily, then close and move to the next. Include: both taps at every sink, the shower, the toilet flush valve (hold it open until pink appears), and the outdoor shower if fitted. Once all lines are pink, pour antifreeze directly into every drain trap and the toilet bowl to protect the P-traps, which the pressurized system does not reach.

• Water heater: Drain the water heater via the drain plug at the base. Allow the heater to cool fully before opening the drain, a pressurized hot tank is a burn hazard. Leave the plug out over winter (store it in a visible location, tape it to the heater access door frame). An anode rod inside the tank should be inspected and replaced if more than 50% corroded, this is a metal rod (usually magnesium or aluminum) that sits inside the tank and corrodes away gradually to protect the steel tank walls from rust. The anode sacrifices itself so the tank does not corrode; a depleted anode means the tank wall starts corroding instead and will eventually fail and leak.
• Fresh water tank: Drain completely via the tank drain valve, usually accessible from a belly compartment or exterior panel. Leave the drain open over winter. Pour a small amount of RV antifreeze into the drain line fitting to protect any residual water trapped in the fitting or adjacent piping.

High-end RVs increasingly include residential-style appliances that each hold water and need their own winterization steps. Treating them as part of the general water system blow-out is not sufficient, each has internal components that trap water in ways that a fixture-by-fixture antifreeze run won't reach.

Regulatory sources for RV winterization: LP gas safety, CO detection, water system sanitation, and motorhome classification. Propane and CO-related incidents during or after storage are the most consequential risks; these sources cover the governing standards.