Everything You Need to Know About RV Antifreeze

WINTERIZING IS AN ESSENTIAL STEP to protect your RV’s plumbing system when temperatures drop, and a key part of that is using RV antifreeze. Still, many RVers have questions about which type to choose and how to use it correctly. 

When RV antifreeze isn’t applied properly, water can remain in the system, causing frozen plumbing, damaged pumps or fixtures, and costly repairs once temperatures rise—all problems winterizing should prevent. So let’s figure out the antifreeze that’s best for your RV and everything you should know about using it the right way.

Key Takeaways

• RV antifreeze protects plumbing by replacing water with a freeze-resistant liquid—propylene glycol (ethanol-free) is the safest choice for potable water systems, while automotive antifreeze must never be used in RV plumbing.
• Most RVs require 2–4 gallons to winterize, ensuring lines, P-traps, and tanks are protected; avoid filling the fresh water tank with antifreeze and instead pump it directly through the plumbing.
• When de-winterizing, flush antifreeze through fixtures and properly dispose of it at a dump station or sewer connection; RV antifreeze is non-toxic but should not be ingested or dumped on the ground.

Need a refresh on how to winterize your RV?

What Is RV Antifreeze?

RV antifreeze does exactly what its name suggests: it prevents the water in your plumbing system from freezing. By replacing the water in your lines with a liquid that has a much lower freezing point, you protect your pipes from expanding and potentially bursting in cold weather. 

Frequently referred to as “the pink stuff”, antifreeze actually comes in a variety of colors—but the color is simply dye added so you can see it in your plumbing lines and has no impact on its performance. 

What does matter is the type of antifreeze you use. 

There are two main types of RV antifreeze you’ll find on the shelf: propylene-glycol blends that contain ethanol and ethanol-free propylene-glycol formulas. Sometimes marketed as “alcohol blend,” ethanol blends are the lower-cost option, but they’re flammable, can dry out seals, often leave a strong taste or smell, and are not considered safe for potable water systems. Ethanol-free propylene-glycol antifreeze is non-toxic, gentle on plumbing components, and is the recommended choice for winterizing RV drinking-water systems.

Some “RV & Marine” antifreezes labeled as “propylene glycol” are actually mixtures of PG and ethanol. They may list PG first, but ethanol is still present and still includes some of the same drawbacks.

RV Antifreeze vs Regular Antifreeze

RV antifreeze and regular automotive antifreeze serve very different purposes, and they are not interchangeable. The antifreeze used in your car or motorhome’s engine is a coolant formulated for high-temperature environments, while RV antifreeze is specifically designed for winterizing plumbing systems.

Ethylene Glycol is the form most commonly used in automotive antifreeze. Propylene glycol is the non-toxic antifreeze used in RV preparations. Since the potable water system can never be 100% cleaned out when dewinterizing, the automotive, ethanol-based products must never be used to winterize the RV.

Technician Tip: Using regular antifreeze in your RV’s plumbing system is dangerous. It can contaminate your water system, damage components, and create a hazardous cleanup. Likewise, RV antifreeze cannot withstand the temperatures and pressures inside an engine.

Is RV Antifreeze Toxic?

Propylene glycol RV antifreeze is a non-toxic solution safe for RV plumbing systems and holding tanks. That said, you should still completely flush antifreeze and sanitize an RV fresh water system when de-winterizing your RV.

You should never dump RV antifreeze directly onto the ground when flushing your system. Improper disposal can allow the solution to leach into soil and waterways, where it may harm plants or aquatic life.

Is RV Antifreeze Toxic to Animals?

When using RV antifreeze or other winterization chemicals, your first step should always be reading the product label. RV antifreeze is formulated to be safe for plumbing systems, but it is not meant for consumption by humans or animals.

Propylene glycol is generally recognized as safe, but pets should never be allowed to ingest it. Ethanol-based antifreeze can be harmful in much smaller amounts. Cats in particular can be sensitive to certain glycols, and dogs may experience illness if they swallow large quantities of any antifreeze.

Fortunately, winterization and de-winterization are short processes. Keep pets indoors while handling antifreeze, clean up any spills, and store containers out of reach.

If your animals accidentally consume RV antifreeze, please seek immediate veterinary attention.

How Much RV Antifreeze Do I Need?

The recommended amount of RV antifreeze for your motorhome or trailer depends on its size. We generally recommend bypassing your water heater—and this is mainly because you’ll need a lot more antifreeze if you don’t.

Most RVs use roughly 2-4 gallons of RV antifreeze, including what goes down the sinks, to ensure any remaining water in the P-traps doesn’t freeze.

Component Definition: P-traps are the U-shaped sections of pipe beneath your sinks that hold water to prevent odors from your gray water holding tank from entering the cabin.

How Much RV Antifreeze to Put in Holding Tanks

Part of winterizing your RV is pouring antifreeze down the sinks to fill the P-traps. Naturally, this will result in some antifreeze traveling through your plumbing and into the gray water tank.

It is recommended that you pour 1-2 cups down each sink. Additionally, you can pour another 2-4 quarts into your RV toilet and then flush the toilet to leave a small amount in your black tank. This can prevent the freezing of residual waste and save you from having to fix a clogged black tank in the spring.

Adding antifreeze to your black water tank isn’t required, but it can prevent leftover tank waste from freezing and damaging the tank. Even if you frequently use your black tank flush to clean your tank as thoroughly as possible, RV holding tanks almost always hold residual waste. A little PG in the toilet and black tank helps prevent the seals from drying out while in storage, too. 

Need a refresher? How to Flush RV Black Tank

How To Get Antifreeze Into RV Lines

When your RV is winterized at a Camping World Service Center, your trained technician will utilize the T-valve before your water pump and connect a hose to pull antifreeze from the bottle into your RV’s plumbing lines. 

You can do this by adding a water pump bypass or disconnecting the line to the pump and connecting a three-foot hose. You’ll need the proper fitting to connect the hose to the pump, and then you can insert the other end of the hose into your bottle of antifreeze to pump it through the system. Before pumping through the system, ensure your water heater is effectively bypassed.

Be sure to read and follow the winterizing directions for your specific water heater, as there are so many different types. We don’t recommend adding antifreeze to your fresh water tank because it can require up to 10 gallons before the pump can pick it up, especially if your tank has a side pickup. The antifreeze will need to completely cover the pickup opening to keep the pump from sucking air. You’ll also need to spend a lot of time flushing the fresh water tank when de-winterizing your RV to get it to stop foaming at the faucets and to eliminate the smell and taste of antifreeze from the system.

Technician’s Tip: To ensure the PG isn’t diluted in terms of strength and temperature protection limits, it is essential to remove as much water from the system as possible before pumping the PG through it. We recommend using compressed air regulated to 30-40 PSI, and opening one side of each faucet at a time until no water or vapor is visible.

If you are not equipped to do this, you can open the low-point drains and every single faucet indoors and out until gravity has pulled out as much water as it can. Then close it all back up and begin pumping the PG through one side of each faucet at a time until the entire system is protected.

How To Flush Antifreeze Out of an RV

Once you’ve winterized your RV, you’ll have antifreeze throughout your plumbing lines, in the P-traps, and a small amount in each of your holding tanks. Before you can safely use your RV’s water system for showering, washing dishes, and drinking, you’ll need to flush all traces of antifreeze.

Here are the quick steps to flushing RV antifreeze:

1. Position your RV near a sewer connection and connect your sewer hose.
2. Connect a potable water hose to your fresh water inlet and fill your fresh water tank.
3. Turn on your water pump to pressurize the system.
4. Open each sink and shower fixture one at a time to run water through your system and into the gray water tank. You can also depress the pedal on your RV toilet to run water through your toilet’s plumbing and into the black tank.
5. Open all outside showers and low-point drains to let them run until clear water comes out.
6. When your gray tank reaches two-thirds capacity, turn off all fixtures and shut down the water pump.
7. Go outside and open the tank valves to drain your holding tanks (black, then gray).
8. Repeat this process at least 2-3 times, allowing the system to sit and soak between each, until the water coming out of your fixtures is clear and completely free of any colored residue that matches the original color of your antifreeze.

Additionally, here’s another refresher on RV fresh tank sanitization.

How To Dispose of RV Antifreeze

RV antifreeze isn’t toxic for your RV’s plumbing, but you shouldn’t dump it on the ground when flushing your system in the spring. Even antifreeze products labeled ‘biodegradable’ should be properly drained into a dump station, septic tank, or residential sewer clean-out.

Please note that non-toxic to humans doesn’t necessarily mean something is non-toxic to other creatures. If any PG is spilled, dilute and rinse it thoroughly with a garden hose.

Automotive antifreeze (EG) is very sweet-tasting and aromatic, and will readily attract dogs, cats, and other animals. However, it is deadly to animals. This should be bottled and taken to your community waste collection center immediately. Some automotive service centers will often accept waste antifreeze and oil. If EG is spilled, extreme care must be taken to clean it up and leave no trace behind. If you cannot move your RV to dispose of antifreeze in one of these locations, you may also empty it into a portable RV waste tank. You’ll then need to transport that tank to one of the aforementioned locations to dispose of it properly.

Does RV Antifreeze Evaporate?

RV antifreeze does evaporate, but at a much slower rate than water. This is one reason it effectively protects your RV’s plumbing for an extended period. PG in the water lines of a winterized RV will last for years if necessary. 

Under the right conditions, however, the antifreeze will evaporate. The first condition is that the antifreeze temperature rises above 223℉—although this is not impossible, it is highly unlikely during winter RV storage.

The second condition is that antifreeze is mixed with water to achieve a 50/50 ratio. This is not recommended for winterizing your RV, but the effect will be a diluted solution that evaporates more slowly than water but more quickly than an undiluted solution.

Does RV Antifreeze Go Bad?

Most RV antifreeze lasts anywhere from 1 to 4 years once opened. Depending on your product choice, your bottle(s) may or may not be labeled with an expiration date. If yours aren’t, a simple test is to shake the bottle and observe the liquid inside. If bubbles appear, your antifreeze has expired.

Here are some tips to maximize your RV antifreeze’s shelf life:

• Only open bottles when you’re ready to use them for winterization.
• Store RV antifreeze in a cool, dry, shaded location.
• Avoid leaving it outside in direct sunlight, especially when temperatures exceed 50℉.

Can You Use RV Antifreeze in a Car or Truck?

No, RV antifreeze and the recommended antifreeze for your automotive are not interchangeable. You shouldn’t use RV antifreeze in an automotive, and you can’t use the same antifreeze you use for your automotive to winterize your RV.

This is because RV antifreeze is specifically designed for use in your plumbing system, while automotive antifreeze is intended for use in the engine. Automotives usually require ethanol-based antifreeze (or an ethylene glycol base), which is toxic and should never be used in your RV’s fresh water system.

If you have a motorhome, you’ll need separate antifreeze solutions for your engine and the RV’s plumbing. The bottom line – find an antifreeze recommended by your automotive manufacturer and use a less toxic propylene glycol antifreeze to keep your RV’s plumbing lines safe during the winter.

Where to Buy RV Antifreeze

Find your nearest Camping World location to pick up RV antifreeze before it’s time to winterize again. Our recommended product is the Champion RV & Marine Antifreeze, but you’ll also need several additional products if it’s your first time winterizing your camper. Use the links below to shop for antifreeze and build your personal winterization kit. 

Use these additional resources to protect your RV (and its plumbing) from extreme temperatures: 

• Winter RV Skirting Tips
• Complete Guide to Winter RV Camping
• Do You Need Covers for RV Tires?
• Choosing an RV Cover for Your Camper

Do you have any other questions about RV antifreeze or its use? Share them in the comments below!