Winterizing is one of those RV jobs that feels simple… until you miss one tiny step and end up with a cracked pipe, a broken pump, or a ruined water heater tank. Learning how to winterize an RV the right way is basically insurance—cheap now, expensive later if skipped.
This guide walks you through a thorough, practical process for how to winterize an RV the right way (without missing anything), including the key places people mess up. If you’d rather have professionals handle it, you can schedule a full winterization service through Daisy RV.
Why Winterizing Matters More Than People Think
Water expands when it freezes. In an RV, that expansion can crack:
- PEX water lines
- Plastic fittings and elbows
- Faucets and shower valves
- Toilet valves
- Outside shower assemblies
- Water pumps
- Water heaters
- Filter housings
The worst part is that freeze damage doesn’t always show itself immediately. You may not discover the leak until the next time you pressurize the system—then you’re chasing wet cabinets and hidden water damage. That’s why doing this carefully is the whole point of how to winterize an RV the right way.
What You Need to Winterize an RV
You can winterize using compressed air, RV antifreeze, or both. Many people use antifreeze because it’s the most foolproof for small low spots and valves.
Here’s a good basic list:
- 2–4 gallons of RV/Marine antifreeze (non-toxic, usually pink)
- Bigger rigs may need more
- Water heater bypass kit (many RVs already have it)
- Basic hand tools (screwdriver, pliers)
- A short hose for siphoning antifreeze (if your RV uses a winterizing pickup)
- Optional but helpful:
- Air compressor + blowout plug (for air method)
- Funnel and/or hose adapters
- A small pan or towels for drips
Important: Use RV/Marine antifreeze, not automotive antifreeze. Automotive antifreeze is toxic and not designed for RV plumbing systems.
Step 1: Dump and Flush the Tanks
Before you start pushing antifreeze through anything, get rid of waste and old water.
- Dump the black tank, then the gray tank.
- Rinse if you have a flush system or use a wand.
- Run some clean water through sinks and shower to clear the lines.
- Empty and rinse your portable hoses if you store them in freezing temps.
This step is part of how to winterize an RV the right way because it prevents waste residue and stagnant water from sitting in the system all winter.
Step 2: Turn Off Water & Relieve Pressure
- Turn off the RV’s water pump.
- Disconnect city water hose.
- Open a faucet to relieve pressure.
If your RV has a water filtration system, now is a good time to remove filters (or bypass them) so they don’t get saturated with antifreeze and/or freeze.
Step 3: Drain the Water Heater (And Bypass It)
This is one of the most important steps in how to winterize an RV the right way—and one of the most commonly messed up.
Drain the Water Heater
- Turn off the water heater:
- Propane mode OFF
- Electric mode OFF
- Let it cool if it was recently running.
- Open the exterior access panel.
- Remove the drain plug or anode rod (depending on model).
- Pull the pressure relief valve briefly to let it drain faster.
Bypass the Water Heater
You do NOT want to fill a 6–12 gallon water heater tank with antifreeze if you can avoid it.
Set the bypass valves to “bypass” mode so antifreeze will flow around the water heater, not into it.
Common bypass setups:
- 3-valve bypass (most common)
- 1-valve bypass on some rigs
- Some older rigs may not have bypass—if not, it’s worth installing.
If you’re unsure which valves to turn, a technician at Daisy RV can set it up and show you exactly what to do for your specific plumbing layout.
Step 4: Drain the Fresh Water System
Now you want to drain as much fresh water as possible from the system:
- Drain the fresh water tank (there’s usually a drain valve underneath)
- Open low-point drains (hot and cold) if your RV has them
- Open all faucets (hot and cold) briefly
- Flush the toilet once to clear water from the line
- Drain the outside shower if equipped
This reduces dilution so your antifreeze stays effective and makes how to winterize an RV the right way much more reliable.
Step 5: Pump RV Antifreeze Through the Plumbing
There are two main methods:
Method A: Use the RV’s Winterizing/Siphon Valve (Most Common)
Many RVs have a winterizing valve near the water pump:
- Locate the winterizing valve and the suction line.
- Turn the valve to “winterize” so the pump pulls from the suction hose.
- Insert the suction hose into a jug of RV antifreeze.
- Turn on the water pump.
Now you’re ready to run antifreeze through everything.
Method B: Use a Hand Pump Into City Water Inlet (Less Common)
Some people use a hand pump to push antifreeze into the city water connection. This works, but the siphon method is usually cleaner and easier.
Step 6: Run Each Faucet Until Pink (Hot and Cold)
This part is where people rush and miss things. Don’t.
Working one fixture at a time:
- Start with the faucet closest to the pump if possible.
- Open the cold side until you see solid pink antifreeze.
- Open the hot side until you see solid pink antifreeze.
Do this for:
- Kitchen sink
- Bathroom sink
- Shower (hot and cold)
- Outside shower (hot and cold)
- Toilet line (flush until pink)
- Any additional sinks, bars, washers, etc.
If your RV has a sprayer faucet or pull-out hose, make sure you run antifreeze through that too.
This is the “don’t miss anything” core of how to winterize an RV the right way.
Step 7: Protect the Toilet, Traps, and Drain Lines
Even if your water lines are protected, your drain traps still hold water—and water freezes.
For each drain:
- Pour a cup or two of RV antifreeze into:
- Kitchen sink drain
- Bathroom sink drain
- Shower/tub drain
This fills the P-traps with antifreeze so they won’t freeze and crack.
Then:
- Add some antifreeze to the toilet bowl (enough to cover the bottom seal).
- Flush a small amount so antifreeze enters the holding tank and protects the valve and seal area.
P-traps and toilet seals are a huge part of how to winterize an RV the right way, because they’re easy to forget and they crack easily.
Step 8: Don’t Forget These Commonly Missed Items
These are the classic “oops” points that lead to freeze damage:
- Outside shower valves (even if you didn’t use it all year)
- Washer/dryer hookups
- Ice maker lines (if equipped)
- Water filter housings
- Low point drains not fully drained
- Sprayer faucets
- City water check valve (some rigs need air method or specific steps to protect it)
If you’re not sure what your RV has, a winterization service at Daisy RV is the easiest way to ensure nothing gets missed.
Optional: Compressed Air Blowout Method (Good Add-On)
Some owners blow out the lines with air first, then use a small amount of antifreeze in traps and valves. This reduces antifreeze use and is effective when done correctly.
Basic approach:
- Use a blowout plug at the city water inlet
- Regulate air pressure (commonly around 30–40 PSI, not extreme pressure)
- Open each faucet one at a time until air-only comes out
- Don’t forget toilet and outside shower
- Still add antifreeze into P-traps and toilet bowl afterward
Air method is effective but easier to mess up if you don’t know your plumbing layout, which is why many people prefer antifreeze-only as the safest version of how to winterize an RV the right way.
Step 9: Final Walk-Through Checklist
Before you call it done:
- Water heater is drained
- Water heater is bypassed
- Fresh tank is drained
- Low point drains opened and drained (then closed)
- All faucets run hot and cold until solid pink
- Toilet flushed until pink
- Outside shower run hot and cold until pink
- Antifreeze added to all P-traps
- Antifreeze left in toilet bowl to protect seal
- Water pump turned off
- City water disconnected and drained
That checklist is basically the “how to winterize an RV the right way” cheat code.
Dewinterizing Tip (So You Don’t Forget Later)
When it’s time to use the RV again:
- Return the water heater bypass to normal
- Install drain plug/anode and fill water heater before turning it on
- Flush lines until clear
- Sanitize system if needed
- Replace water filters
A shocking number of water heaters get destroyed because someone turns on the electric element before the tank is full.
Learning how to winterize an RV the right way is all about being methodical and not rushing the boring steps—because the boring steps are what prevent cracked pipes and expensive repairs.
If you’d rather have it done professionally (and know it’s done correctly), the RV technicians at Daisy RV can winterize your rig thoroughly, check for weak points, and help you avoid the “first spring trip surprise leak” that ruins so many seasons.