Fresh Water Tank While Towing.

[{Tpc}]

I prefer to tow without water in the tanks. Prefer. There are times where I know we will be boondocking, so I always try to find a place nearby with potable water, so that the distance while towing will be short. But i've had no issue going 50 or so miles with a full tank. Other than losing part of it. My tank has an overflow on each side with a tube the ejects underneath the trailer. It is not a gravity fill. So basically I fill it up till some comes out and I know its full. However the slant of the ground determines which side it will come out of and movement down the road will knock a little out as well.

I also think the ports are installed a little "low" so I never quite get a full tank. But with 2 grays and a black, I can fill it up a second time maybe more before the waste tanks are full. Again, at that point I will drive with them like that to the nearest dump. Haven't had an issue so far, knock on wood.

 

[markltorrey]

We picked up our new Cougar 25MLE in mid February 2025, and cold (30's) temps, so had the dealer "winterize" the unit, filling the freshwater tank about ⅔ full with partial non-toxic antifreeze. We towed it home in 37˚F and rain, about 65 miles with no issues, or perceptive sway. I don't know if the fresh water tank has baffles but will find out.

A separate issue now is flushing the fresh water tank...

 

[rlh1957]

FW tanks don’t usually have baffles and it doesn’t matter when traveling. No problem traveling with FW tank filled. You don’t need to worry with sway unless the rest of the trailer is grossly overloaded toward the rear.
Your weight on your placard sticker on the left of camper is calculated with FW Tank filled.
Besides you don’t know if water will be available before or at your destination campground. At least carry 1/2 tank of FW.

Unless you’re heading north and into another month of day time temp below freezing and nights in low 20’s or teens you don’t need winterizing now.

You’ll have to drain the fresh water tank and purge the whole system of antifreeze. Hookup & Run city water or fill FW tank and run each faucet until clean, clear & no foaming.
After water system is purged you can take HW tank out of bypass & run HW from faucet to make certain it flows without any air spitting.
Only then can you turn on electric to HW heater or light off on propane.

 

[workinonit]

I'm filling ours for this upcoming trip. I have to have some good water for tea and cooking. I never put that anti-freeze in any of my water lines. That taste takes forever to dissipate.

 

[NH_Bulldog]

FW tanks don’t usually have baffles and it doesn’t matter when traveling. No problem traveling with FW tank filled. You don’t need to worry with sway unless the rest of the trailer is grossly overloaded toward the rear.
Your weight on your placard sticker on the left of camper is calculated with FW Tank filled.
Besides you don’t know if water will be available before or at your destination campground. At least carry 1/2 tank of FW.

Unless you’re heading north and into another month of day time temp below freezing and nights in low 20’s or teens you don’t need winterizing now.

You’ll have to drain the fresh water tank and purge the whole system of antifreeze. Hookup & Run city water or fill FW tank and run each faucet until clean, clear & no foaming.
After water system is purged you can take HW tank out of bypass & run HW from faucet to make certain it flows without any air spitting.
Only then can you turn on electric to HW heater or light off on propane.

With all due respect, several of your statements are overly broad and/or incorrect for this situation.

The cargo/loading sticker is the place to look for weight capacity, but every model is different as to what is included in weight calculations. My Passport was calculated with fresh water full and all other tanks empty but my Cougar was calculated with propane tanks full and all other tanks empty (including fresh water). Location of the water tank determines weight carrying performance characteristics and whether sway could be a factor. Additionally, since they started using tankless water heaters a few years ago, there is no water heater bypass.

 

[ADQ K9]

I always leave with a full FW tank I have shown up @ full hookup campgrounds and they might have water issues so it is good to have a full tank of water on board
Semper Paratus

 

[JRTJH]

We picked up our new Cougar 25MLE in mid February 2025, and cold (30's) temps, so had the dealer "winterize" the unit, filling the freshwater tank about ⅔ full with partial non-toxic antifreeze. We towed it home in 37˚F and rain, about 65 miles with no issues, or perceptive sway. I don't know if the fresh water tank has baffles but will find out.

A separate issue now is flushing the fresh water tank...

Are you sure about that ??? Your fresh water tank is listed as 54 gallons. To fill it 2/3's full is about 36 gallons. RV antifreeze at dealerships is around $5/gallon. That's roughly $180-200 just for antifreeze. Unless you paid extra for the materials PLUS LABOR, to the tune of around $300-400, I'd suspect the dealer didn't spend that much money to do something nearly all dealers avoid... That's put a large amount of antifreeze in the fresh water tank...

I'd suspect that if your dealership "re-winterized your trailer", he may have put a couple gallons of antifreeze "through the water pump and into the plumbing runs" but none in the fresh water tank...

While it's "possible" that your dealer poured 35+ gallons of "red stuff" into your fresh water tank, it's highly unlikely that happened. I'd urge you to crawl under your trailer, open the fresh water tank drain and see what comes out. My guess is that it won't be red, but rather will be clear water (if anything) and your plumbing runs (PEX tubing) is all that's filled with antifreeze. If I'm correct, then you still need to "sanitize" your fresh water system, but I don't believe you have that much antifreeze in your fresh water tank.... Let's hope not, at least....

As for cargo weight and whether fresh water/waste water are included, there are as many different ways to document that "VIN/WEIGHT" decal as there are model years for trailers and manufacturers of RV's.... Then, there are TWO decals on the side of recent trailers. One, the white one, has a statement to clarify whether water is included or omitted as cargo weight... Then there's the yellow decal that states "Maximum cargo is xxxx" It typically DOES NOT include water as trailer weight, but includes it in "max cargo weight". So, if you "do the math" you'll see that both the white decal and the yellow decal "say the same thing" but on one, water may/may not be included and on the other, it typically is NOT included...

EVERY TRAILER CAN BE DOCUMENTED DIFFERENTLY !!!!! Confirm how your decals reflect your trailer, and don't rely on a post on this forum as "the way it is for every trailer"....