Frozen pipes do not announce themselves. They crack, then they leak where you cannot see the damage for months, and the first sign is a water stain on a wall in spring. Winterizing your RV plumbing is the one seasonal chore with no real downside to doing early and a very expensive one to doing late. This guide walks the whole system in the order that protects it: drain, bypass the water heater, protect every line and trap, and then undo it correctly in spring.
Last reviewed: Sep 21, 2026, against current manufacturer winterization guidance. We update these guides when real-world data changes.
Where to get the gear. These are the maker's own product pages: Camco RV antifreeze, the Camco pump converter winterization kit, and the Camco blow-out plug. Other brands work fine; the important part is the label, RV and marine antifreeze, never automotive.
Antifreeze only protects what it reaches. Every drop of water left in a line, a tank, or a pump is a potential ice pocket, so the draining step is the foundation of everything that follows. Give it the time it deserves; a hurried drain is how lines crack.
Open the fresh tank drain valve and let it empty completely. Prop the valve open while you work so any remaining water keeps dripping out.
Underneath the RV, usually near the centerline, you will find one or two low-point drain valves or caps, one for the hot line and one for the cold. They are often colored or labeled, red for hot and blue for cold. Open both. Missing a single low-point drain is the most common beginner error, a closed valve holds enough water to cause line damage overnight, and it is exactly the kind of crack you will not find until spring.
Open both sides of every faucet, plus the outdoor shower if you have one, so air can enter the lines and water can leave them. Flush the toilet until the bowl is dry. Leave everything open while you work so the system keeps draining.
Turn off the water heater on both gas and electric. Let the water cool, then open the pressure relief valve so air can enter the tank. Remove the drain plug at the bottom, on the exterior access panel, and let the tank drain completely, which takes several minutes for a 6 or 10 gallon tank. Open a hot faucet inside as you drain so the lines behind it empty too.
The plug in the bottom of the water heater depends on the brand. Suburban water heaters use a steel tank with a sacrificial anode rod. The rod is 9 inches of metal that protects the tank by corroding in its place, and the hex head on the drain plug is the anode. While it is out, inspect how much rod remains. Atwood and Dometic heaters use an aluminum tank with a simple plastic drain plug and no anode rod. Do not install an aftermarket anode rod in an Atwood aluminum tank; the metal reaction can seize it in the threads. Whichever brand you have, if any part of the rod or plug looks badly consumed, replace it now with the proper part for your heater.
Behind the water heater, often under a removable panel, are the bypass valves, most RVs use a one or three valve setup. Their job is to route water around the heater instead of through it. On a three valve system, the common arrangement is the inlet and outlet valves closed and the center bypass open. Turn the handles perpendicular to the pipes to close, parallel to route flow. Confirm the bypass by tracing both the hot and cold feed lines visually. If antifreeze later flows into the tank, the bypass was not fully set, and you will waste several gallons trying to make pink show at the faucets.
Leave the plug out or loosely in place until spring. The tank must stay empty. If you are storing outdoors, many owners reinstall the plug loosely or screen the opening so nothing crawls in while still letting the tank breathe and stay dry.
RV antifreeze is propylene glycol, formulated for drinking water systems and safe for the pipes. It protects by replacing the water in the lines with liquid that will not freeze, so even a missed pocket of moisture is diluted into a mix that survives. The method has two ways to feed the system.
The pump winterizing kit, preferred: find the water pump, where the suction line normally draws from the fresh tank. Switch the diverter or attach the siphon hose so the pump draws from a hose dropped into the antifreeze jug instead. This is the clean way and uses the least antifreeze; most modern RVs have the valve factory-installed, and if yours does not, a pump converter winterization kit adds one in minutes.
Pouring into the fresh tank, the fallback: drain the tank first, leave the drain closed, pour two to four gallons of antifreeze into the tank, and pump it through from there. It works, but it takes more antifreeze and leaves the tank itself full of pink, which must be flushed in spring.
Method at the faucets: start at the faucet farthest from the pump and work inward. Turn on the pump, open the cold side until pink runs steadily, close it, open the hot side until pink runs, close it, and move to the next fixture. Cover every faucet, the shower head, the outdoor shower, the toilet flush until pink appears in the bowl, and any washing machine or ice maker connection your RV has.
A compressor blows the water out of the lines with air, leaving the system dry instead of filled. It is faster and leaves no pink taste to flush in spring, but it has to be done thoroughly, because a single trapped pocket of water is still water, and it will still freeze.
The settings that matter: screw a blow-out plug into the city water inlet, connect the compressor, and set it to 30 to 40 psi. Do not exceed 50 psi, pressure above that can damage the lines and fittings. Work one valve at a time, opening each faucet until it spits only air, and repeat around the whole RV, including the shower and toilet valve. Wear eye and ear protection; a blowing line is loud. When the air runs clear, close everything and disconnect.
Use both for the best result. Many experienced owners blow the lines out first and then run antifreeze through them, which protects the plumbing two ways: the air removes the bulk of the water, and the antifreeze covers whatever the air missed. It uses less antifreeze than the antifreeze-only method and adds a second layer of certainty.
The sink and shower drains do not connect to the pressurized lines you just protected, and the water sitting in their curved P-traps is exactly what freezes and cracks first. Pour about a cup of antifreeze down the kitchen sink, the bathroom sink, the shower drain, and any floor drain, so the traps hold pink instead of water. This is the most skipped step in winterizing, and it is the one that produces the mysterious bathroom-sink crack in spring.
A filter full of water will freeze and split its housing. Remove the cartridge, store it inside the RV, and cap or open the filter housing so nothing holds water.
Empty both waste tanks completely, at a dump station or approved drain. Water left in the bottom of a holding tank can freeze and warp the tank or crack the valve. Leave the valves open or cracked afterward so nothing collects.
If your RV has a heated wet bay, clean the strainers and confirm the heater works before you need it. If the bay is not heated, insulate the compartment and, on cold nights, use a small heater or a 60-watt incandescent bulb, but only if the setup is safe to leave unattended. Many owners simply winterize the entire bay and stop worrying about it.
Undoing winter is easier than doing it, but the order still matters. Sanitize the fresh system first, then flush the pink out, then restore the water heater.
Winterizing is a system, not a checklist of favorite steps. The failure points are the water left behind, the heater left full, and the traps left unprotected. Drain completely, bypass the heater, fill the traps, and the rest of the job is routine. One careful afternoon now beats $1,500 of pipe and cabinet work in March.
About 2 to 3 gallons for a typical travel trailer, more for large fifth wheels and motorhomes with extra loops such as outdoor showers or washing machines. 4 to 6 gallons covers even the big RVs. If you blow the lines out first, you need much less.
Never. Automotive antifreeze contains ethylene glycol, which is toxic and will poison the drinking water system. RV antifreeze is propylene glycol, non-toxic and made for potable plumbing. The two are different chemicals and are not interchangeable.
Set the compressor to 30 to 40 psi and never exceed 50 psi, which can damage lines and fittings. Work one faucet or valve at a time until each spits only air, and wear eye and ear protection. Many owners follow the air blow-out with antifreeze for double protection.
The pink stays in the lines until you flush it. Fill the fresh tank, run every faucet until the pink is gone, and drain once more. Sanitizing the system first with a bleach solution or commercial sanitizer helps. Never mix bleach and antifreeze in the same pass; flush between them.
If you are certain the compartment cannot freeze, you can leave it, but draining is free and forgetting costs a tank. A partially full water heater is a classic crack point, and most technicians drain them every winter regardless of the forecast.