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Winterizing an RV can prevent costly repairs down the line. How much RV antifreeze to put in holding tanks will depend on the size and model of your RV.

When water freezes, it expands and can cause pipes to burst. In a stationary home, this can be avoided by properly insulating the home. However, RV life can take you on some cold adventures. If an RV’s pipes and tanks freeze and burst, it can be a costly repair for the owner and leave them stuck in one place until a specialist can perform repairs.

When you winterize your RV, you will need to put 2-4 gallons of RV antifreeze in each holding tank. The exact amount you need will depend on the size of your rig, the model of the RV, and if you have holding tank heating pads.

RV antifreeze is non-toxic so it can be used for fresh water tanks in addition to gray water and black water tanks. After you initially winterize your RV, it will be important to add more antifreeze over the course of the winter so that it does not become too diluted to be ineffective. RV antifreeze can be added to the tanks directly using a hand pump; it can also be poured down the drain or flushed down the toilet.

Sources include RV Life, Campanda Magazine, RV Lifestyle, and The RV Travel Guide.



What is RV Antifreeze?

RV antifreeze is a special kind of antifreeze that is non-toxic so that it can be used in plumbing systems. It is not the same as automotive antifreeze, which is toxic. RV antifreeze is normally pink and comes in a jug with a square base.

Non-toxic antifreeze for RV is alcohol-based; Certain alcohols like ethanol and propylene glycol can raise the freezing point of water, which will prevent your pipes from freezing. Both ethanol and propylene glycol antifreeze brands are good for winterizing RVs. However, a few small side effects have been reported with both products.

Some RV owners who used ethanol antifreeze during the winter reported tasting it in the water when they started traveling for the summer again. Ethanol can also have a corrosive effect on the rubber seals in the plumbing.

Antifreeze with propylene glycol is sometimes made from recycled materials, which can harm your plumbing system after repeated uses. If an antifreeze brand touts its recycled status, buy a fresh gallon instead.

Regardless of the complaints, RV antifreeze is still one of the best ways to protect your pipes and holding tanks from freezing. A few jugs of antifreeze are far cheaper than repairing a busted pipe. The key to using antifreeze responsibly is to properly flush the pipes before adding it and after winter ends.

Which Holding Tanks Do I Put Antifreeze In?

All modern RVs have 3 different tanks: fresh water, gray water, and black water. As it sounds, fresh water is the water that comes out of the sink and the shower. It is clean and safe to drink. Gray water is the water that goes down the drain after a shower or doing dishes. This water is not very clean, but it may be used to water plants or rinse off the RV in a pinch. Black water is what gets flushed down the toilet; it doesn’t smell great and will need frequent emptying.

Fresh water, gray water, and black water tanks all require antifreeze to prevent the tanks from being damaged in the event of a freeze. However, the methods for adding antifreeze to these 3 tanks are slightly different.

Adding Antifreeze to the Fresh Water Tank

Before you can add antifreeze, you must completely drain your fresh water tank. Some RV owners flush the plumbing with compressed water to completely clear out any lingering moisture in addition to using antifreeze.

Once the tank is completely drained, use a hand pump to add 2-4 gallons of pink antifreeze to the tank. Larger RVs will require more and smaller rigs will not need as much.

After the required amount of antifreeze has been added, turn on the shower, all the faucets, and flush the toilet. When you see pink water coming out, you can turn off the water.

Alternatively, if you purchase and install a 3 way valve, it allows you to bypass the fresh water tank completely while still protecting your RV’s plumbing system.

Not all RV owners use antifreeze in the fresh water tank. Even though RV antifreeze is non-toxic, many people don’t want it in their shower water or near their food. Depending on the model of your RV and your destination, you may be able to get away with using antifreeze only in your gray water and black water tanks.

How to Add Antifreeze to the Gray Water and Black Water Tanks

When you turn on the faucets and flush the toilet to run antifreeze through your fresh water plumbing, it will dump the remaining antifreeze into the gray water tank and black water holding tank. This is not adequate winterizing for your RV. By the time the antifreeze has circulated through your rig and come out the faucet, it is too diluted to be completely effective for your other 2 holding tanks.

The good news is that adding antifreeze to the gray water and black water tank is very easy.

First, you must completely empty both the gray water and black water tanks. Add RV antifreeze to the gray water tank by pouring 2-4 gallons down the sink drain. You can either flush 2-4 gallons of antifreeze down the toilet or add it directly to the black water tank with a hand pump.

How Much RV Antifreeze Should I Put in My RV’s Holding Tanks?

The recommended amount of antifreeze for your RV tanks varies depending on the size of your rig. Generally 2-4 gallons per tank is recommended. For most RVs, 2 gallons per tank is adequate to prevent the pipes from freezing.

The rule of thumb for most RV owners is to use 1 gallon of antifreeze if the RV does not have holding tanks. This works for teardrop trailers, built out vans, and smaller RVs that only have a small fresh water reserve and a small gray water tank. 1 gallon of antifreeze should be more than enough to line the pipes and prevent any damage.

If your RV is under 18 feet long, experienced RV owners will instruct you to use 2 gallons of antifreeze per tank. However, if your destination is chilly but not below freezing, you may be safe using the runoff antifreeze from the fresh water tank to winterize the gray water tank. It all depends on your destination and how your RV is built.

For RVs that are 18 to 28 feet, it is recommended that you use 3 gallons of antifreeze per tank initially. You may need to add more over the course of the winter to prevent it from becoming too diluted.

If your RV is over 29 feet long, you will need 4-5 gallons of antifreeze, depending on the exact size and the length of the plumbing system.

Unless someone else has the exact same make and model RV as you, it can be hard to tell exactly how much antifreeze you should use. Every RV is built differently and has a different plumbing system. These guidelines are a good place to start. If you are traveling somewhere with temperatures below freezing, you may need to use more antifreeze. If you can taste or smell antifreeze in the water, that is your sign to use a little less.

Over time, you will develop a system for winterizing your RV and you will know exactly how much antifreeze your rig requires.

Is There an Alternative To Putting Antifreeze in My RV Tanks?

If you don’t want to use antifreeze in your RV, you do have other options, such as RV tank heating pads, RV skirting, heated hoses, and upgrading to an RV designed for winter travel.

Antifreeze is one of the cheaper options for protecting your RV. However, if you enjoy traveling to cold climates throughout the winter, it may be worth the cost to invest in a lower maintenance winterizing method.

RV Tanks Heating Pads

RV tank heating pads are electric heaters that are glued to the bottom of your fresh water, gray water, and black water holding tanks. The pads are wired into the RV’s electrical system. When you have your heating pads installed, you will get a set of switches in the cab so that you can turn on the heaters when you need to.

Tank heating pads are only applied directly to the 3 holding tanks, but they normally give off enough residual heat to reach the pipes as well.

RV Skirting

RV skirting is a method of insulating your RV’s plumbing by wrapping the base of the rig to keep the heat in. If your RV is stationary throughout the winter, RV skirting is a great option for winterizing. You can easily make RV skirting yourself with some styrofoam and wood or buy it pre-made.

Since RV skirting can be heavy, big, and hard to move, this isn’t a very practical solution for travelers who are mobile all winter. Some companies sell inflatable skirting that can be utilized on the road, but it still adds another step for you to pack and unpack on each leg of the journey.

Heated Hoses

One of the biggest nuisances with winter camping is frozen tubing when you try to dumb gray water or black water. One way to avoid this is with heated hoses. Much like heating pads for the tanks, heated hoses plug into your RV’s electrical system. Hoses are not much help if your tanks or other areas of your plumbing freeze, but they can make emptying the tanks easier in the winter.

Upgrade to a Winter RV

If you find yourself in 40 below weather frequently, it may be worth it to invest in an RV designed for winter conditions. Most RVs are meant to be driven only during the summer months. Many RV builders expect RV owners to head south for the winter, so standard RVs are not designed for winter travel.

Several manufacturers build RVs that are specifically designed for winter use. This means that the plumbing is heated and insulated to prevent it from freezing. With most winter RVs, you will never need to add antifreeze to the tanks.