RV Anti-Freeze

We have a Fleetwood Regal Prowler. It is a seasonal unit, set up at a campground year around. We are hooked up to city water and so do not use the fresh water holding tank. Can I pour 12 or more gallons of RV antifreeze into the tank and use what I need to winterize the trailer each year from what I have stored in the fresh water tank? And an important question, does the stored antifreeze remain stable or does it deteriorate?
Richard, (Oshkosh, WI)

I see no reason not to attempt what you are suggesting Richard. As long as you never need on-board, self-contained fresh water, why not use the fresh water storage tank as an anti-freeze holding container? RV anti-freeze will have a shelf life, but I do not know how long it will actually stay viable, so check with the suppler to be sure of its life expectancy. I’m sure the producer of that brand will have what’s called an MSDS sheet that should help shed some light on its lifespan.

And I’m certain you would not require twelve gallons of it to properly protect your Prowler. I do recommend a water heater by-pass kit to keep the anti-freeze cost down though. I would venture you’d be able to safely use the same anti-freeze for a minimum of at least two years. You can always test its effectiveness after that by using a coolant hydrometer. I’d run a little through the water pump as well to keep the gaskets and seals moist in there since you never use the pump while on city water. But, shoot….I’d say go for it since you employ city water all the time. If need be, it can always be flushed out later.