If you want to winterize your camper, there’s one thing above all else: water must not be allowed to freeze anywhere it could cause damage. A burst pump, a cracked faucet, or a leaky water heater are typical examples of frost damage you’ll see in the spring. With the right approach, winterizing your camper can be done in one to two hours.
Whether you have a camper, a van, or an RV: In this post, we’ll show you three things: how to properly winterize your camper in the fall, what to do if you still need to use it occasionally during the winter, and how to prepare the tank and lines for the season again in the spring when you take it out of winter storage.
What kind of winter user are you?
How you winterize your camper depends on how you use it during the winter.
Camper is parked from fall through spring
Fill the water system with antifreeze, leave the battery connected to the charger, and keep the interior dry.
Here’s what you’ll need: LILIE Winter Ban, tank cleaner, charger
Continue to Part 1: WinterizingCamper is used occasionally
Leave the fixed water system empty or drain it after every trip; bring water in a canister.
What you’ll need: water canister, drain valve, antifreeze monitor
Continue to Part 2: Winter Use
Part 1
Winterizing Your Camper in the Fall
This section is for you if your camper is stored from fall through spring. Prepare it for winter before the first night frost, not after.
1. The water system is the most critical part
Water expands by about 9% when it freezes. This is rarely a problem in the tank, where the ice has room to expand. The critical areas are the narrow passages:
- Water pump
- Faucets and mixer taps
- Water heater
- Filter housings and hose connectors
That’s why it’s not enough to simply empty the water tank. Residual water almost always remains in the pump, faucet, and water heater. It is precisely this residual water that causes freeze damage.
2. Our favorite: LILIE Winter Ban instead of the tedious draining process
You have two options: drain and blow out the entire system, or fill it with an antifreeze solution designed for drinking water systems. We’re big fans of the second option with LILIE Winter Ban.
Winter Ban is based on propylene glycol. It’s non-toxic, tasteless, and odorless, and designed for drinking water and fresh water systems. Here’s why it’s a good choice:
- protects against frost damage at outdoor temperatures as low as −45 °C
- No need to remove the pump or fittings
- lubricates pumps and valves over the winter
- protects against corrosion, scale, algae, and bacterial growth
- requires no electricity or heating
Here’s what to do
- Completely empty the fresh water tank.
- Drain the boiler. If your boiler does not have a bypass, the solution will flow through the boiler later. In that case, add the volume of the boiler’s contents to the total amount.
- Remove the filter cartridges and store them in a frost-free location. Fine membrane filters cannot tolerate frost.
- Pour Winter Ban into the empty tank.
- Turn on the pump and open each faucet individually—both cold and hot—until the solution reaches the faucet. Don’t forget the shower and outdoor shower.
- Pour a splash of Winter Ban down each drain. This will also protect the siphon.
- Empty the wastewater tank and leave the drain valve open.
For the pipes, pump, and faucets of a typical camper van, one 3.78-liter canister is usually sufficient. You can pour in Winter Ban undiluted for maximum protection. If you dilute it, follow the mixing chart on the canister.
The alternative without antifreeze: Empty the tank, boiler, and pipes; leave all faucets open in the middle position; and let the pump run dry for about 30 seconds. This works, but it’s more time-consuming and there’s still a risk of residual water. A drain valve at the lowest point of the line makes draining much easier.
3. Clean the tank before winterizing
Clean the tank before winterizing. Otherwise, the biofilm will remain in the tank throughout the season. Two simple methods:
- AbtyCAM Fresh Water Tank Cleaner: 1 measuring spoon per 10 liters of water; let it sit for 2 hours, then pump it out. Rinsing is not necessary. As it flows out, the cleaner also cleans the wastewater tank.
- WM aquatec DEXDA Clean: the thorough option for combating biofilm and germs when the water already smells musty.
You can find more about the setup of the tank, pump, and filter in the article “The Perfect Water System in a Camper.”
4. Winterizing the Battery and Electrical System
It’s best to leave the battery connected to the charger all winter.
This applies to both lead-acid and lithium batteries.
If that’s not possible for you, make sure the battery is fully charged at least once every two months: using solar power, a charge booster, or an external power source. “Fully charged” means up to the cut-off voltage. For all our batteries, that’s 14.6 V.
Important for lithium batteries: Lithium batteries won’t accept a charge when their core temperature is below 0 °C. If it’s very cold, heat up the camper first—for example, using the auxiliary heater. The auxiliary heater should be run at full power for 30 minutes every now and then anyway to prevent it from getting clogged with soot. So you can combine both steps.
Turn off silent consumers
Even when everything in the camper is turned off, standby loads can drain the battery over the course of months.
- Turn off the main switch. The main switch disconnects the smaller appliances from the battery. It does not disconnect larger appliances that are connected directly to the battery. You can see how this is wired in our electrical diagram.
- Set the discharge switch to OFF. Our 120 Ah and 200 Ah lithium batteries have a discharge switch on the case. When it’s set to OFF, even the larger devices no longer draw power. The discharge switch doesn’t replace the charger; it provides additional protection.
Also remember the starter battery if the camper is parked for a long time.
5. Interior: Preventing Moisture and Mold
Moisture is the second biggest enemy when winterizing a camper, after frost.
- Remove all food and liquids
- Clean the refrigerator and leave the door slightly ajar
- Properly position the upholstery and open cabinets and drawers to allow air to circulate
- Empty and clean the toilet
Here’s an idea as an extra precaution: Set up a dehumidifier and check it every few weeks.
6. Vehicle and Auxiliary Heater
- Wash the camper, including the roof and solar panels. Dirt, leaves, and bird droppings can damage the paint and seals if left for months. That’s why we have Solbio Car Shampoo. According to the manufacturer, it’s suitable for all types of paint and is safe for acrylic glass.
- Check the seals on windows, skylights, and feed-throughs. Water can seep in through a leak all winter long, and you won’t notice it until spring.
- Increase tire pressure slightly. Tires lose air over the course of months. A little extra pressure helps prevent flat spots.
- Release the parking brake, put the car in gear, and place chocks under the wheels. A parking brake that’s left engaged can rust solid over the winter.
- Check the antifreeze in the radiator and windshield washer system. Without enough antifreeze, the water will freeze and damage the radiator, reservoir, and hoses.
- Fill up with winter diesel before storing the vehicle. Summer diesel separates in cold weather and clogs the filter. This makes it difficult or impossible to start the engine or the auxiliary heater.
Run your diesel auxiliary heater about once a month even in winter, always for at least 30 minutes at full power. If it runs for a shorter time or only on a low setting, it will become clogged with soot. In cold weather, this will also warm up the lithium battery for charging.
Part 2
Using Your Camper Occasionally in Winter
A ski weekend, a few days over New Year’s: If you need to use the camper occasionally in winter, “Winter Ban” is too much of a hassle. You’d have to flush the system before every trip and refill it afterward. These tips and tricks are easier.
7. Water: Three Options When You Need Your Camper in Winter
Leave the fixed system as is for the winter
This is the simplest solution. The tank and lines remain filled with Winter Ban. For your trip, bring a 10- to 20-liter water jug and place it inside the heated cabin. That’s enough for two or three days of cooking, brushing your teeth, and washing dishes.
Fill as usual, empty after every trip
As long as the heater is running and the tank and lines are inside the camper, nothing will freeze. It only becomes a problem when the camper is parked in the cold again. So after your trip, you’ll need to:
- Empty the tank and water heater.
- Open all faucets to the middle position and leave them open.
- Let the pump run dry for about 30 seconds.
- Hang the showerhead downward so the hose drains.
It’s even easier with a freeze protection valve. The valve is located at the lowest point of the water system, requires no power, and opens automatically when the ambient temperature drops below about 3 °C. You can also open it manually. Don’t install it right next to the heater, or it will activate too late.
Heat Vulnerable Areas
If your tank is located under the floor or in an unheated area, a 12-V tank heater can help. The self-adhesive heating film turns on automatically below +7 °C. If a wastewater pipe or drain valve does freeze, the LILIE heating tape will thaw it out using the 12-V outlet.
Tip for wastewater: A wastewater canister inside the vehicle won’t freeze. If you have an underfloor tank, leave the drain valve open in winter and place a portable wastewater tank or bucket underneath it.
Part 3
Winterizing Your Camper in the Spring
As soon as there are no more nights with freezing temperatures forecast, get the water system ready for the season again. Set aside half a day for this, because the cleaning agents need time to take effect.
8. Rinse out the Winter Ban
- Drain the Winter Ban through the faucets or via the drain valve. Catch it and dispose of it through the wastewater system, not on the grass.
- Fill the tank with fresh water.
- Flush out each faucet individually—both hot and cold—including the shower and outdoor shower.
- Empty the tank and repeat the process once more.
9. Clean, descale, and disinfect the water tank
Now is the best time for a thorough cleaning. The product you need depends on the problem:
Limescale provides a base for biofilm. That’s why it’s worth descaling and disinfecting in the spring. According to the manufacturer, KXpress and DEXDA Clean can be used in the same cycle. With Solbio, too, the descaler is added in the same step as the water tank cleaner. Always follow the instructions on the bottle regarding dosage and contact time.
Which product is right for you? In the Water Hygiene Comparison Sheet: All Products Compared (PDF), you can see all the products side by side. For Solbio, there’s also the Solbio Product Comparison Sheet (PDF).
Tip: Use the built-in LILIE Tornado to rinse the inside walls of the tank. Connect the garden hose to the outside, and the spray head rotates 360° inside the tank.
10. Keep water fresh for the season
A clean tank will only stay clean if you preserve the water.
- Certec Drinking Water Preservative: The capsule floats in the tank, dispenses automatically, and remains effective for up to 12 months. It’s available for tanks up to 30 liters and up to 100 liters.
- Silver Net Flex: Releases silver ions every time the tank is filled. Replace once a year.
- Micropur Classic: 1 ml per 10 liters of water; keeps clear drinking water fresh for up to 6 months.
Be sure to install new filter cartridges now as well. For the wastewater tank, Awiwa Fresh is a biological additive that helps eliminate odors. You can find all products in the Water Hygiene category, and a comparison of all products in the Water Hygiene Comparison Sheet: All Products Compared (PDF).
11. The Rest of the Spring Checkup
- Turn on the pump and check all hose connections for leaks. If the pump keeps starting up even when the faucet is closed, there’s a leak somewhere.
- Turn on the main switch, set the battery back to ON, and fully charge it again
- Test the auxiliary heater, CO detector, and gas detector
- Adjust tire pressure to normal levels
- Check the seals and roof vents
- Ventilate the interior thoroughly
Bottom line: Winterizing your camper properly once will save you a lot of trouble in the spring
Winterizing your camper isn’t rocket science. If your camper will be stored until spring, fill the water system with Winter Ban, leave the battery connected to the charger, and keep the interior dry. If you need to use it in the meantime, leave the built-in system winterized and bring water in a canister. In the spring, flush, clean, and preserve the tank, and you’re ready for the season.
Not sure what’s right for your camper’s layout? Stop by our store in Winterthur with your camper. In-store consultations are free and come with no obligation to buy.
In-Store ConsultationFrequently Asked Questions About Winterizing Your Camper
When should I start winterizing my camper?
Before the first night frost. In the Swiss Mittelland, this is usually between late October and mid-November; at higher elevations, it’s earlier. As soon as nighttime temperatures are forecast to drop below 0 °C, there should be no water left unprotected in the system.
Is it enough to just empty the water tank?
No. Residual water remains in the pump, faucets, water heater, and filters. You must either drain the entire system, including the pipes, or fill it with an antifreeze agent such as LILIE Winter Ban.
Is Winter Ban toxic?
No. Winter Ban is based on propylene glycol; it is non-toxic, tasteless, and odorless, and is designed for drinking water and fresh water systems. In the spring, flush the system thoroughly before refilling with drinking water.
How much Winter Ban do I need for my camper?
For the pipes, pump, and fittings of a typical van, one 3.78-liter canister is usually sufficient. If you have a water heater without a bypass or very long pipes, you’ll need more.
Can the LiFePO4 battery stay in the camper during the winter?
Yes. It’s best to keep it connected to the charger all winter, whether it’s a lead-acid or lithium battery. If that’s not possible, fully charge it at least once every two months. Lithium batteries won’t accept a charge when their core temperature drops below 0 °C. In very cold weather, you should therefore heat up the camper first.
Can I still use the camper in winter if it’s winterized?
Yes. Leave the fixed water system winterized and bring water in a canister into the heated interior. That way, you won’t have to drain anything after your trip.
How often should the auxiliary heater run in winter?
About once a month, and always for at least 30 minutes at full power. If the diesel auxiliary heater runs for a shorter period, it will become clogged with soot.
How do I clean the water tank in the spring?
First, flush out the antifreeze, then clean it with a tank cleaner and descale it if necessary. Afterward, fill it with fresh water and treat it with a drinking water preservative.
