A pipe split by freezing water is the most common preventable RV repair. The damage hides until spring, when the first water-on test reveals leaks behind walls, under cabinets, and inside the water heater. A proper winterization routine takes 60 to 90 minutes in the fall and prevents the problem entirely. This checklist walks through the process step by step.
What you need
Two to four gallons of pink RV antifreeze (propylene glycol, drinking-water rated), a water heater bypass kit if not already installed, a water pump converter kit ($15 to $30 inline part) or a hand-pump siphon, basic hand tools (pliers, screwdriver), and a bucket for catching water at low-point drains.
The exact antifreeze quantity depends on rig size: small Class B vans use about 2 gallons; mid-size Class C and travel trailers use 3 to 4 gallons; large Class A coaches with multiple bathrooms use 4 to 6 gallons.
Step 1: Drain the fresh water tank
Open the fresh water tank drain valve, usually located on the underside of the rig. Open every faucet (hot and cold) and the toilet to release vacuum. Let the tank drain completely. Run the water pump for 15 to 30 seconds to clear residual water from the line between the tank and pump. Turn the pump off.
Leave the fresh tank drain open during storage so any condensation can escape.
Step 2: Drain the water heater
The water heater is the most commonly damaged component in a freeze, because the 6 to 10 gallon tank holds enough water to develop serious freeze pressure.
Turn off the water heater electric switch and shut off the propane at the tank. Wait 1 to 2 hours for the water inside to cool to safe temperatures, or longer if the unit has been running recently. A scald injury from removing the drain plug on a hot water heater is a real risk.
Once cool, open the pressure relief valve on top of the water heater, then remove the drain plug (a 1 1/16 inch socket or the Camco wrench-style drain) at the bottom. Catch the water in a bucket or let it run on the ground if outside.
A water heater rinse wand fits into the drain opening and rinses out accumulated mineral deposits. Use it every fall as part of winterization to extend water heater life.
Reinstall the drain plug. Leave the pressure relief valve open.
Step 3: Set the water heater bypass
The water heater bypass is a set of valves (factory-installed on most rigs) that route hot and cold lines past the water heater. The bypass keeps antifreeze out of the water heater tank, which would otherwise consume 6 to 10 gallons of antifreeze for no benefit.
Most rigs have either a single-valve or three-valve bypass. Set all bypass valves to the “bypass” position per the owner’s manual. If the rig lacks a bypass, install a kit ($20 to $40, requires basic plumbing skills) before winterizing.
Step 4: Open low-point drains
Most RVs have low-point drain valves at the lowest point in the hot and cold water lines, usually accessible from underneath. Open both valves and let any residual water drain out.
Close the low-point drains before pumping antifreeze through. Leaving them open will dump antifreeze on the ground instead of pushing it through the system.
Step 5: Pump antifreeze through the system
Two methods work. The simpler one uses a water pump converter kit: a short hose that screws into the pump inlet and runs into the antifreeze jug. Disconnect the line from the fresh tank to the pump and connect the converter hose instead.
Turn the pump on. The pump pulls antifreeze from the jug and pushes it through the plumbing.
Open each faucet one at a time, hot side first, then cold side, until you see solid pink antifreeze running out (no clear water mixed in). Close that faucet and move to the next. Cover the shower head with a plastic bag during this step to catch sprays. Flush the toilet until pink antifreeze appears in the bowl. Do not forget the outdoor shower and any flush valve on the black tank flush connection.
Pour a cup of antifreeze down every drain (kitchen sink, bath sink, shower, toilet) to protect the P-traps and prevent the tank vent from creating a vacuum during storage.
Step 6: Holding tanks
The fresh tank should be empty and dry. The black and grey tanks should be drained but do not need to be empty of all liquid; a small amount of water plus a cup of RV antifreeze in each tank is fine.
Some owners run a full dump and tank flush before winterizing so the tanks store as clean as possible. This is good practice and reduces spring odors.
Step 7: Final checks
Inside the rig, verify that the water pump is off and disconnect the city water inlet (no hose attached). Open the fridge and freezer doors so they air out during storage; close them only if a fridge fan accessory keeps air moving. Pull the battery disconnect or remove batteries for separate storage if storing more than 2 months.
Outside the rig, check the propane tanks. Some users leave them off; others leave the gas on for a fridge running in storage. The decision depends on local code and security.
Storage considerations beyond water
A full winterization is more than plumbing. The complete fall storage checklist includes: full fuel tank with fuel stabilizer added (gas degrades over 3 to 6 months), tire pressure set 5 psi higher than running pressure to compensate for cold-weather drop, slide-outs retracted and seals clean and conditioned with Protect-All or 303 Aerospace, awning rolled and clean, vent covers in place, rodent traps or peppermint oil deterrents in the engine bay and storage compartments.
De-winterization in spring
The reverse process is faster. Open every faucet, low-point drain, and the toilet flush; let antifreeze drain. Refill the fresh tank with clean water. Run the pump and flush every tap until water runs clear with no pink tint. Reset the water heater bypass to normal, refill the water heater (open hot water faucet to let air escape), turn the water heater back on, sanitize the system with a bleach solution per any standard RV water system guide.
For ongoing water system care, see our guide on RV water systems and our /methodology page.
The honest framing: winterization is one of the few RV maintenance tasks where a single mistake can cause four-figure damage. Take the 90 minutes once per fall, follow every step, and the system stays intact for another season. A neglected winterization is the most expensive shortcut in RV ownership.
Frequently asked questions
When should I winterize my RV?+
Before the first night of sustained sub-32F temperatures in your area. Water expands roughly 9 percent when it freezes, which is enough to split copper, PEX, and brass fittings. A single hard freeze can crack the water heater, the pump, the water lines, and the valves. In cold climates this means mid-October to early November; in milder areas, December or January depending on local forecasts. If a single overnight freeze is in the forecast and the system is not winterized yet, run the furnace and keep the cabin above freezing as a temporary measure.
How much RV antifreeze do I need?+
Two to four gallons of RV-specific non-toxic antifreeze for most rigs, depending on plumbing length and number of fixtures. A small Class B uses about 2 gallons; a full-size Class A with multiple bathrooms can use 4 to 6 gallons. Use only pink RV antifreeze (propylene glycol), never automotive antifreeze (ethylene glycol), which is toxic. Camco and Splash brands are both common and rated for drinking-water systems.
Should I use the blow-out method or antifreeze method?+
Antifreeze is more reliable for most users. The blow-out method (using compressed air to push water out of every line) works in skilled hands but leaves residual moisture in low spots, which can still freeze. Antifreeze leaves a known protective fluid in every line. Some full-timers use a combination: blow out the lines first, then pull antifreeze through. For most weekend and seasonal users, antifreeze alone is the simpler reliable choice.
Do I need to drain the fresh water tank?+
Yes, completely. A full or partially full fresh tank that freezes can crack the tank itself, which is an expensive repair. Open the low-point drain valve and the tank drain valve, run the pump dry for 30 seconds to clear it, then leave the drains open during storage. Do not put antifreeze in the fresh tank; it is wasted and adds cleanup work in the spring.
How do I de-winterize the RV in spring?+
Drain all the antifreeze first by opening every faucet and low-point drain. Refill the fresh tank with clean water, then sanitize the system with a bleach solution as described in any standard RV water system guide. Run the pump until clean water flows from every tap with no pink tint. Reconnect the water heater bypass to its normal position and refill the water heater. The full process takes 30 to 60 minutes.
