New Complete RV Winterizing

A comprehensive guide to properly storing your trailer or motorhome until spring.

Story and Photos by Perry Mack

We feel this is the most complete winterizing article that we’ve put together with updated information for 2022/2023 and RV innovations designed in the last five or six years. Properly storing your motorhome or trailer for the winter doesn’t take long and you’ll get back more than what you put into it with an easy start-up in the spring. Let’s get started and have some fun doing it.

Assuming you have to park your RV outside (as it’s not always an option to store it in a temperature-controlled storage facility), avoid parking it under trees to eliminate sap, needles and leaves from accumulating on the roof. If you don’t have a gravel or cement pad, park your tires on 30 x 30 cm (12 x 12 in) pieces of wood to help protect them. Although we’ve never done it, you can jack your RV up by the frame so your tires don’t touch the ground to prevent flat spots. This is only necessary for storage of longer than six months.

Water System Antifreeze

You’ll need one to three jugs of antifreeze, depending on the size of your RV. If it’s your first-time winterizing your water system, buy three or four, saving any open leftovers for next year. You may also need an anti-freeze kit, which includes a hand pump.

Myths and Facts

  1. Whether anti-freeze ‘freezes’ or not isn’t important. What is important is that it doesn’t expand when it freezes. Water expands as it forms a crystalline structure and can damage your water system. Most RV antifreeze will turn slushy before hitting the maximum rated cold temperature and that’s OK.
  2. You need to add RV antifreeze because it is going into your potable water system. It’s non-toxic and non-staining. Always use RV antifreeze as automotive antifreeze is poisonous.
  3. Most antifreeze is pure or has a blend of ethanol or propylene glycol. Both compounds are non-toxic and biodegradable.
  4. The goal is not to add it to the water in your system, it is to replace it. Your RV antifreeze will have a ‘no-burst’ rating down to -50°C or -60°C (-58°F or -76°F), but it won’t if it’s diluted with water.
  5. Winterize your plumbing system by using air pressure to blow out the lines but you’ll still need to add antifreeze to the P-traps. If too much water is retained it will freeze and burst a line. If you apply too much air pressure you can damage the system.

Winterize Your Plumbing System

  1. Empty your black and grey water tanks at a dump station.
  2. Turn off the water heater. Leaving it on may cause you to get scalded while draining the tank. If it drains but remains on, you’ll damage the element.
  3. Tilt your trailer towards the water drain(s) so gravity does most of the work to get the water out. You may have two drain lines - one for the freshwater tank (usually blue) and one for the water heater (typically red). Depending on your RV, remove the drain plug(s) or open the valve.
  4. Open all cold and hot water faucets to drain the lines in the kitchen, bath(s), shower, tub, outdoor shower and other lines for the dishwasher or washing machine.
  5. Flush the toilet.
  6. Make sure the water heater is off, open the pressure relief valve and drain it (you may have to remove the anode rod). Replace the anode rod once it’s drained and apply some Teflon tape on the threaded fittings to reduce the chance of it leaking in the spring.
  7. You don’t want antifreeze to fill the heater so it will have to be closed to the system. Check your manual to see if your RV has a water heater bypass or locate the water heater and shut the incoming cold-water valve. It’s usually the lower water line (blue) and the upper hot water line is red.
  8. Most RVs have a winterizing line. You can buy a kit from your RV dealer. Close the line to the freshwater tank and open the pump suction line. Turn on your pump for 15 seconds to drain the pump. Don’t let it run any longer as you can damage it by running it too long without water.
  9. Close all the taps you opened earlier.
  10. Place the suction hose into your jug of antifreeze and turn on the pump. The antifreeze will now get sucked into the lines. When one jug empties, replace it with the next. Turn on the hot and cold taps in the kitchen until you only see pink antifreeze coming out. Now, do the same for bath, shower, tub and exterior shower and/or other systems. Flush the toilet and let it flush until you see pink and about 500 ml has passed through into the black water tank.
  11. Many, if not most, RVs come with a sani-flush feature, which is also called a sewer flush or blackwater tank flush. This system is independent of all the other plumbing systems so it has to be winterized separately. Water from the outside connection goes to a backflow prevention device (often located in your bathroom vanity) and then to a sprayer in your blackwater tank. Both may have some water in them, which could cause them to freeze and crack. So, you’ll need to put antifreeze into the exterior line with a hand pump or a long extension funnel. You may be fortunate enough to have an RV with an exterior water supply fixture near the sani-flush. In this case, it’ll have a hose that connects the two so your sani-flush will be winterized with the rest of your system.
  12. Then pour 500 ml of antifreeze down the kitchen, bath, and shower/tub drains. This will fill the P-traps with anti-freeze and prevent damage.
  13. If you have a washing machine, dishwasher, or ice maker read the manuals and follow the winterizing instructions.

Winterizing Your Batteries and Proper Maintenance

If you leave the batteries connected in your RV, odds are they will drain entirely and become damaged, even if you have a battery disconnect. It’s always best to at least disconnect one wire from each battery.

The best technique is to pull the battery(s) (negative cable first) from the RV, store them in a warm, dry place (not the concrete floor of your shed) and put a battery tender on them over the winter. Most chargers are designed for automotive use and are for 12V systems. Your RV battery may be 6V so your tender needs a 6V setting. If you have two 6V batteries you can connect them in a series and use your 12V tender.

Battery tenders are different from battery chargers as tenders ‘exercise’ your batteries by drawing a small charge and then adding small amounts back, which is how a battery is designed to work. You use them while boondocking and then re-charge them while connected to shore power, using a gen set and/or when driving (if you have a motorhome or often when you are towing using a 7-pin connector).

This is also a good time to top up the electrolyte if you have flooded lead-acid batteries and clean any corrosion from the battery posts and leads on the RV. Corrosion on the terminals causes resistance to charging and discharging. In other words, your battery has to work harder and can sometimes create hot spots, which means it won’t last as long. If you leave them connected to the RV or when you reinstall them in spring, apply a terminal coating spray to prevent corrosion.

Check your charging system. We can tell you that your batteries can get damaged if they are being over- or under-charged. Do a little research to find the tools and techniques or consult with your RV technician.

Wash, Seal and Wax

Some of the grime on your RV is potentially damaging, especially road salt, road tar, bugs, bird droppings, and tree sap. Completely clean the exterior including the roof, checking all the seams and caulking for any cracks. Re-seal and patch if necessary. Then apply a coat of wax as it serves as a barrier against UV damage, dirt, and abrasion.

Don’t forget your awning

It will no doubt be a cool or overcast day when you winterize your RV so it’s easy to forget about the awning. Open, clean it, and then make sure it’s completely dry before you close it. You don’t want rotting pine needles or leaves in there with moisture that can cause mould and mildew. Also, clean other fabric or canvas materials.

AC Maintenance

While you’re on the roof cleaning it, replace the AC filters. Whatever it filtered out through the summer could still be in there and now is the time to evict dust, debris, mould, mildew and even nesting insects.

Locks and Hinges

Lubricate the locks and hinges to eliminate moisture so it doesn’t freeze and cause damage. This will also help eliminate most creaks, squeaks and jams in the spring.

Dehumidify

If you have power and can check on your RV in the winter, run a dehumidifier once a month. If you don’t have power, use a moisture-absorbing product like DampRid or Camco’s Moisture Absorbing Bucket.

Protect Against Rodents

Rodents in an RV are a bad thing. The droppings can carry disease and they stink. Pests will also destroy anything that can be used to make a nice nest where they can breed and turn your RV into an apartment complex.

Now add some scents that rodents find repelling like peppermint oil, mothballs, dryer sheets, or bars of Irish Spring soap. In case they still come in, you can add traps or poisons. We hesitate to start with traps or poisons as we’re concerned the bait might attract them. Check your RV once a month for rodent infestation.

We use a rodent repellant on all the surfaces they may crawl onto like the jacks and tires. In case they get past that, we'll also put a rodent repellant inside the RV.  If possible, park your RV on a hard surface rather than grass or in a field. For motorhomes, put a mesh screen or steel wool in the tailpipe so critters don’t move in for the winter.

Take Cover

Double check that all roof vents are closed. Unless your RV will be undercover, you can leave them open 5 mm to allow some air circulation. Make sure your tires are properly inflated. Then pull out your tire covers. Give them a coating of rodent repellant inside and out before using them. Then, put the cover securely over your RV if you have one. Read our article about RV Storage Options for more info on covers.

With these measures in place, you can sleep easily through the winter knowing your RV is safe from damage and look forward to spring adventures with a trailer or motorhome that is eagerly awaiting the first sunny, warm days of spring.