Anti freeze into fresh water tank

Not that RV antifreeze is toxic because it isn't in diluted amounts and commercial bakers use it as a dough extender but, if you like foamy water all season long and that slight aftertaste of antifreeze in your coffee..

By all, means dump a couple gallons in your FW rank and pump it through your system and...

Then post on here next spring about how you can get rid of the foam and slight antifreeze taste. Makes for interesting reading...

I have done it that way, but like someone pointed out it takes more antifreeze. I have a Wayne 12 volt pump that hooks to the battery.I use it to put water in the tank if we have no campground water connection.But it also works great for putting antifreeze in. I stick the pick up end in the bottle and the other end attaches to the fresh water connection.Of course I drain everything and blow out lines first.It takes about 1.5 gallons of antifreeze to purge the lines. Then I use another 1.5 gallons in the traps and the holding tanks.

As stated, my pickup point is about 2 inches off the bottom of the tank and the drain is off the pickup line. This leaves 2-3 gallons in the tank. Wasted anti-freeze and difficult to get rid of.

When I winterized our first Class A many years ago, I did the "anti-freeze in the tank" thing. Never again! That old 1977 Pace Arrow not only didn't have a pickup tube for the pump, it didn't have a water heater bypass system! It took nearly 10 gallons of "pink stuff" to winterize the water system, and getting the taste out of the system was extremely difficult and wasted many gallons of fresh water.
Since then, I have winterized the RVs exactly the same way one would winterize an underground sprinkler system: 55 to 60 PSI air, then about a cup of AF in each P trap and in the toilet.
15 minutes of air compressor use, and half a gallon (or less) of AF, and I'm done.
It works for me.

On my rv when you drain the Fresh Tank there are a couple gallons left in it. YOu don;t' want to know how I had to get it out (Thankfully I was able to do it)

I do not recommend using Pink Stuff in the fresh system at all. Compressed air is the key, blow it out and forget it (Blow like 10 times with a few minutes betwen blows, all valves including low point open) If the air in the lines ever freezes.. You won't be worried about it.

No reason to leave anti-freeze in the line after replacing the water. I put it in the tank and pump it around. Then I open the fresh tank drain and drain it all back into the jug to use next year.

My tank drain is at the back bottom of the tank and putting a slight up tilt on the 5er gets it to all drain. I then open the low point drain and blow compressed air through the lines and get the last of the antifreeze out of the line. I add some to the P traps and that is all I loose from year to year is the cup or so in the traps.The water out of the fresh tank and lines has never had any antifreeze I could detect come out of the faucet after I blow it out back into the jug.

Never have a residual of antifreeze in the lines come spring. I flush with bleach water each spring so if there was a drop or two it would come out then.

Gettin anti freeze into the tank is the easy part. Getting ALL the antifreeze out of the tank is the hard part.

Rather than dump anti-freeze into the tank...why not just get an air compressor, set the outgoing pressure to 40psi and blow out the lines? Then a cupfull of pink antifreeze into each trap (split whatever is left over between the toilet and the shower.

I've dumped antifreeze in the FW tank and pumped it through the system. It worked and I never had a problem.
But, I have started to just blow out the lines and use antifreeze in the traps.

because the idea here is to get the job done with the least amount of the pink stuff. I can do my entire TT with a gallon of pink and that includes drains. If you have money to burn go for it.