RV 101® – RV Antifreeze – What you need to know

RV & Marine Antifreeze

What is RV & Marine antifreeze?

Can RV antifreeze freeze solid?

How do you winterize the RV plumbing system against freezing?

Is RV antifreeze toxic to humans and pets?

Where can I get more safety information about RV & Marine antifreeze?

Does RV antifreeze leave a bad taste in the plumbing system?

How do you sanitize the RV water system after de-winterizing?

What does GRAS on the RV & marine antifreeze label mean?

Let’s start with the basics

Glycol, what is it?

In simple terms Glycol is an antifreeze. Glycol is used in automotive antifreeze and in RV and marine antifreeze. What is important for RV and boat owners to understand is, the type of antifreeze used in automotive and industrial applications (Ethylene Glycol) is toxic to humans and pets. The type of antifreeze used in RV and marine applications (Propylene Glycol) is food grade antifreeze and it is non-toxic to humans and pets.

Caution:  Although propylene glycol antifreeze is non-toxic food-grade antifreeze, it can still be harmful to pets if ingested in sufficient quantities. Always dispose of RV & marine antifreeze properly.

Automotive Antifreeze

Automotive Antifreeze

Automotive antifreeze (Ethylene Glycol) protects the water in the engine from freezing, and it keeps the engine operating at its most efficient temperature regardless of operating conditions and outside temperatures, and its help prevent scale and rust build-up in the cooling system and engine.

Caution: Ethylene glycol antifreeze is poisonous to humans and pets, so it needs to be disposed of properly. Never use automotive antifreeze in the freshwater plumbing system of an RV.

RV & Marine Antifreeze

RV & Marine Antifreeze

RV antifreeze (Propylene Glycol) is designed to protect RV and marine potable water systems from freezing which results in costly damage. The minus 50-degree F, and minus 75-degree F RV & marine antifreeze is typically pink in color. The minus 100-degree F RV & marine antifreeze is typically blue (purple/blue) in color.

What does minus 50-degree, minus 75-degree and minus 100-degree protection mean?

RV & Marine antifreeze protects against what is referred to as “burst protection” not necessarily against freezing, and this is important to understand. Damage to a plumbing system when it freezes is caused by the ice in the plumbing line or fitting freezing, expanding and rupturing. The rupturing part is what you don’t want to happen to your RV’s plumbing system.

The Burst Point

RV antifreeze rated for minus 50-degree F will start to freeze at about +20-degrees F. RV antifreeze rated for and minus 75-degree F will start to freeze at about +16-degrees F.  But neither will freeze (solid) to the burst point until minus 50-degree F or minus 75-degree F respectively. So, in extreme cold temperatures it’s not uncommon for the antifreeze to appear slushy. When the temperature rises again the slush will disappear.

In areas of the country (and for are friends up north) where temperatures go into minus digits and stay there for days on end, you should use the minus 100-degree F antifreeze for added protection. This type of antifreeze protection will start to freeze at about minus 20-degrees F, but it won’t freeze (solid) to the burst point until minus 100-degrees F.

PEX plumbing

RV & marine antifreeze is compatible with all types of plumbing materials like copper, PVC, PEX, and more, but to be on the safe side read the label on the container prior to using. When the antifreeze container specifies RV & Marine it means it is designed to protect potable plumbing systems. If you see GRAS on the RV antifreeze label or in advertising, it means all the ingredients are considered (generally regarded as safe) by the food and drug administration.

RV 101 Tip: If you are winterizing a boat engine, make sure the antifreeze you use is made specifically for use in boat engines.

Safety Data Sheet (SDS)

When a company manufactures and/or distributes chemicals, they are required to have a Safety Data Sheet for the end user. When I was in the military these were called Material Safety Data Sheets (MSDS), but now they are referred to as Safety Data Sheets (SDS). The SDS is designed to inform the end user of any hazards associated with the chemical. The SDS also includes useful information about using and storing the product, safety precautions, health hazards and more. If you want more information about RV & marine antifreeze just search for the manufacture’s Safety Data Sheet in your Internet browser.

Draining the plumbing system

Drain those water lines!

freeze damaged water line

Something else important to understand is you need to evacuate as much water from the plumbing system prior to adding the RV antifreeze, because diluted water and antifreeze can freeze and burst sooner than the rated temperatures you see on the container.

Next spring, when you de-winterize the RV plumbing system the RV antifreeze can leave an unwanted taste in the water system. I usually sanitize the RV plumbing system when I take the RV out of storage, and/or there are products you can add to the plumbing system that will clean and refresh the water system. If you want to sanitize the RV water system yourself, check this video out.

If you want to learn more about winterizing and de-winterizing your RV, or you want to do the job yourself, check out our Winterizing & Storing your RV Online Training Course.

Happy Camping,
Mark Polk
RV Education 101


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