How to Winterize an RV Before Freezing Temperatures Arrive
The basic goal is simple:
Remove as much water as possible from the RV plumbing system and protect the areas where water may remain.
There are two common ways to winterize an RV:
Pump RV antifreeze through the fresh-water plumbing system.
Use compressed air to blow water from the plumbing lines.
This guide walks through both methods.
Every RV is a little different, so familiarize yourself with your own plumbing system before you begin.
Before You Start Winterizing Your RV
Before doing anything else, make sure you understand where the important components of your RV water system are located.
You should know how to find:
Freshwater tank drain
Low-point drains, if equipped
Water pump
City-water connection
Water heater
Water-heater bypass valves
Kitchen faucet
Bathroom faucet
Shower
Toilet
Outside shower or exterior faucet
Some RVs may have additional plumbing fixtures or appliances that also need attention. The sooner you identify these components, the easier winterizing becomes.
Important Water-Heater Safety
Before draining the RV water heater, turn it off and allow it to cool completely. Also turn off the water pump and disconnect or turn off the city-water supply. Once the water heater has cooled and no pressurized water source is connected, carefully open the pressure-relief valve to release any residual pressure inside the tank.
Never remove the water-heater drain plug or anode rod while the tank is hot or pressurized.
That is one step where there is no reason to hurry.
Method 1: How to Winterize an RV With RV Antifreeze
Using RV antifreeze is a common way to protect the fresh-water plumbing system during winter storage. Make sure you are using antifreeze intended for RV and marine potable-water systems. Do not use automotive engine antifreeze in the RV fresh-water system.
Step 1: Drain the RV Water Heater
Once the water heater is cool and depressurized, remove the drain plug or anode rod.
Atwood/Dometic: drain plug or cap
Suburban: anode rod, commonly removed with a 1-1/16-inch socket
Allow the water heater to drain completely.
Once drained, you can also flush the tank to remove sediment that has collected inside. Your winterizing guide recommends flushing it for approximately two to three minutes or using a water-heater flushing tool for a more thorough cleaning.
If you removed the anode rod, inspect its condition. Replace it before the RV goes back into service if needed.
Step 2: Bypass the RV Water Heater
Do not pump RV antifreeze through the water-heater tank.
Bypass the water heater before introducing antifreeze into the rest of the plumbing system.
Without a bypass, you may unnecessarily fill a six- to ten-gallon water-heater tank with RV antifreeze. Your original guide recommends installing a permanent bypass kit if one isn’t already installed.
Many RVs already have water-heater bypass valves.
You generally access the front of the water heater through the exterior service door.
You usually access the plumbing connections and bypass valves from the rear of the water heater through an interior cabinet, removable panel, or access opening.
Set the valves to the winterizing/bypass position before pumping antifreeze through the RV.
What About On-Demand RV Water Heaters?
On-demand water heaters can have different winterizing requirements.
Follow the manufacturer’s winterizing procedure for the specific water heater installed in your RV. Your existing guide specifically calls this out because the procedure may differ from a conventional RV tank-style water heater.
Step 3: Drain the Freshwater Tank
Turn off the water pump and disconnect the RV from city water.
Open the freshwater tank drain and allow the tank to empty.
If your RV has low-point drains, open those as well.
Low-point drains may use:
Drain valves
Removable caps
Approximately 1/2-inch drain fittings
Not every RV has low-point drains.
Opening the faucets while the system drains allows air into the plumbing and can help the water drain more quickly and thoroughly.
Once the initial draining is complete, close the faucets and position the low-point drains as needed for the next part of the winterizing process.
Step 4: Set Up the Water Pump for RV Antifreeze
Many RVs have a winterizing hose or conversion kit installed near the water pump.
This lets the pump draw antifreeze directly from the antifreeze container instead of pulling water from the freshwater tank.
If your RV already has a winterizing kit:
Place the winterizing hose into the RV antifreeze container.
Position the valve correctly.
Turn on the water pump.
The pump should begin drawing RV antifreeze into the fresh-water plumbing system.
Step 5: Winterize the Exterior Plumbing Fixtures
Your original procedure recommends starting with the lower and exterior fixtures and working through the system.
If appropriate for your RV, open the low-point drains until pink antifreeze appears, then close them again.
Next, move to the exterior plumbing fixtures.
These may include:
Outside shower
Exterior faucet
Wash station
Outdoor kitchen
Operate one side of the faucet at a time.
Run the cold side until pink RV antifreeze appears.
Close it.
Then run the hot side until pink antifreeze appears.
Close it and move to the next fixture.
Step 6: Winterize the Interior Faucets
Now repeat the same procedure inside the RV.
Work through:
Kitchen faucet
Bathroom faucet
Shower
Other interior faucets
At each fixture:
Open the cold-water side.
Let it run until you see pink RV antifreeze.
Close the cold side.
Open the hot-water side.
Let it run until you see pink antifreeze.
Close it.
The pink antifreeze tells you that RV antifreeze has displaced the water in that section of plumbing.
Step 7: Do Not Forget the Toilet
The toilet is connected to the freshwater plumbing system too.
Operate the toilet flush pedal or hand flush until RV antifreeze flows through the toilet valve and into the bowl.
It is an easy component to overlook, but the toilet water valve and supply line also need protection from freezing.
Step 8: Drain the Black and Gray Holding Tanks
Prepare your holding tanks for storage.
Your original winterizing instructions suggest doing the final holding-tank drain toward the end because some water and antifreeze may enter the tanks while you winterize the plumbing system.
Drain the:
Black tank first.
Then drain the:
Gray tank.
Clean and flush the tanks as needed, then perform a final drain so they are as empty as practical before storage.
Leaving wastewater or significant amounts of liquid in the tanks through freezing weather can create unnecessary problems.
Step 9: Protect the P-Traps
The plumbing lines are only part of the system.
Water also remains in the P-traps underneath sinks and showers.
Pour some RV antifreeze into each drain, including:
Kitchen sink
Bathroom sink
Shower
Other drains
This leaves antifreeze in the trap instead of plain water.
Your original instructions also call for adding antifreeze to the toilet area as part of the final winterizing process.
Step 10: Do a Final Walk-Through
Before calling the job finished, walk through the RV one more time.
Verify that you have addressed:
Water heater
Water-heater bypass
Freshwater tank
Low-point drains
Water pump
Kitchen faucet
Bathroom faucet
Shower
Toilet
Outside shower
Exterior faucets
Black tank
Gray tank
Sink and shower P-traps
Also double-check that the water heater remains turned off.
That last point is important when the water heater tank is empty.
Method 2: How to Winterize an RV With Compressed Air
Another method is to use compressed air to blow water from the RV plumbing system.
The basic idea is different from pumping antifreeze through every water line.
Instead, you:
Drain as much water as possible.
Bypass and drain the water heater.
Connect regulated compressed air to the city-water inlet.
Blow the remaining water from the plumbing fixtures.
Your existing winterizing procedure recommends keeping the compressed-air pressure between 30 and 50 PSI.
Step 1: Drain the Black and Gray Tanks
Start by emptying both wastewater holding tanks.
Drain the black tank first and then the gray tank.
The objective is to avoid leaving wastewater or unnecessary liquid in the holding tanks during freezing weather.
Step 2: Drain the Freshwater Tank and Low-Point Drains
Turn off the water pump and disconnect the city-water supply.
Open the freshwater tank drain.
Open the low-point drains if your RV has them.
Opening the faucets will help the freshwater system drain faster and more thoroughly.
Once the initial draining is complete, position the drain valves or caps as needed for the remaining procedure.
Step 3: Bypass the Water Heater
Also place the water heater in bypass mode when winterizing with compressed air.
Locate the bypass valves at the rear of the water heater and position them so you are working with the RV plumbing system rather than trying to send compressed air through the water-heater tank.
Step 4: Drain the Water Heater
Just as with the antifreeze method:
Turn the water heater off.
Allow it to cool.
Turn off the water supply.
Release the pressure.
Remove the drain plug or anode rod.
Allow the tank to drain.
You may also flush the water heater at this time to remove sediment.
Again:
Never remove the drain plug or anode rod while the tank is hot or pressurized.
Step 5: Open the Faucets
Open the plumbing fixtures inside and outside the RV.
Your original guide specifically mentions:
Bathroom faucet
Kitchen faucet
Outside shower
Cleanup or exterior faucet
Toilet
Operate the toilet until the water stops flowing.
Allow as much water as possible to drain naturally before introducing compressed air.
Step 6: Run the RV Water Pump Briefly
Turn the water pump on briefly to help remove water remaining around the pump and freshwater side of the system.
Once water stops coming from the faucets or toilet, turn the pump off.
Don’t leave the pump running dry.
Step 7: Install the Blow-Out Adapter
Install an RV blow-out adapter at the city-water connection.
Connect the air hose from the compressor to the blow-out adapter.
Regulate the air supply before introducing compressed air into the RV plumbing system.
Step 8: Blow Out the RV Water Lines
Your existing procedure specifies an air pressure of approximately:
30–50 PSI
Do not set the pressure above the recommended range for the RV plumbing system.
Introduce compressed air into the system and work through the plumbing fixtures until water no longer sprays from the faucets and valves.
The objective is not simply to push a tremendous amount of air through the plumbing.
It is to remove the water without unnecessarily pressurizing the system.
Step 9: Check the System Before Storage
When you are finished, inspect the RV one final time.
Check the:
Faucets
Valves
Low-point drains
Freshwater drain
Water-heater bypass
Exterior plumbing fixtures
Make sure everything is in the proper position for winter storage.
Which RV Winterizing Method Is Better?
No single winterizing method is right for every RV owner. Some RVers prefer pumping RV antifreeze through the plumbing system because it gives them the visual confirmation of seeing pink antifreeze at every fixture. Others prefer using compressed air because less antifreeze is being pumped through the freshwater plumbing.
The important thing is not which method your neighbor uses.
It is that your RV’s plumbing system is properly protected before freezing temperatures arrive.
Whichever method you choose, understand your RV before you start.
When Should You Winterize Your RV?
Do not base the decision entirely on the calendar.
Watch the overnight forecast.
September may still provide beautiful camping weather in many parts of the country, while another region could already be experiencing freezing nights.
What matters is the temperature your RV will actually experience.
If freezing temperatures are approaching and the RV will be sitting unused, it is time to have a plan.
That is especially important when the RV is stored somewhere you cannot quickly get to it if the forecast changes.
Winterizing an RV Is Easier When You Prepare Early
Most winterizing problems do not happen because the procedure itself is incredibly difficult. They happen because someone is trying to do everything at the last minute. It is 30 degrees outside. The antifreeze is still at the store. Nobody remembers where the bypass valve is. You’ve never located the low-point drains.
And suddenly a routine maintenance job becomes an emergency. Spend a little time learning your RV now. Know where everything is. Have your supplies ready.
Then when the forecast finally calls for freezing temperatures, you can take care of the RV without rushing.
At what temperature should I winterize my RV?
You should have the RV prepared before freezing temperatures arrive. Do not wait until after the RV has already been exposed to an extended freeze to start thinking about winterizing.
Do I need to bypass the RV water heater when winterizing?
When using the RV-antifreeze method, the water heater should be bypassed so you do not unnecessarily fill the water-heater tank with several gallons of antifreeze. Your existing procedure also calls for bypassing the water heater when using the compressed-air method.
Do I need to drain the RV water heater?
Yes. Your winterizing procedure calls for draining the water heater with either method. Turn it off, allow it to cool, remove the water pressure, and then drain the tank.
How much pressure should I use to blow out RV water lines?
30–50 PSI and Do Not Exceed
Do I winterize the toilet?
Yes. When using the antifreeze method, operate the toilet until pink RV antifreeze flows through the toilet valve and into the bowl. The toilet also needs to be included when draining or blowing out the system.
Should I leave water in the black and gray tanks for winter?
It is recommended draining and cleaning both tanks and performing a final drain before winter storage.
