Going to a campsite, fill the water tank or not?

Jay_and_Kat

Knowing that having the water tank filled (potable, not the waste-water tanks) will impact the tongue weight of a camper (and never having towed before,) I've got a question.

If you're going to a campsite that does not have a water hookup or a "fill station" to fill the water tank before going to your site, do you fill the tank at home before hitting the road?  Or do you partially fill it, or find someplace with an unwatched hose spigot and sneak a fill in?  (I'm joking on that last, it'd be stealing and it'd be wrong!)

Sharon_is_SAM

The fresh water tank is positioned over the axle of the TaBs and should not have much impact on tongue weight.  Obviously it adds to the total TaB weight and reduces your fuel economy with towing.

Regarding when to fill up, I think it depends on where you are headed.  Out west there are gas stations that supply fresh water (refueling is a nice thing to do here).  If you are simply moving from a site with a water hook up, the answer is easy.  Some do travel with full tanks, keeping in mind your total GCWR.

falcon1970

You don't say what trailer you have (400 or 320) but the center of gravity of the fresh water tank in a TAB 400 sits very close to the axle and doesn't affect the tongue weight much at all.  It will add to the total weight of the trailer though.  I believe you should tow with either an empty tank or a full tank whenever possible to prevent "sloshing" of the water in a partially filled tank.  However, "sloshing" is probably not a major factor in a 40 gallon tank. If you anticipate needing fresh water, and there won't be water available at the campsite, I would suggest filling it at home and towing a full tank to your campsite.  I don't believe a full fresh water tank will adversely affect the towing characteristics of your trailer and it is always nice to have water available.  On the return trip, if you are going directly home, you can open the fresh water tank drain valve and drain any remaining water while you drive.  Probably not a good idea to drain the gray and/or black water tanks while you drive though.  At least not if I am behind you!!

kottum

A full water tank is weight carried very low, and near the center of the trailer.  This is very desirable for trailer stability (rollover and sway). 

On the other hand, loading gear high in the trailer, and at the back of the trailer, will contribute to less trailer stability (rollover and sway).

Wind resistance will have a much greater effect on fuel economy than added weight.  Once at speed on fairly level roadway, this added weight means almost nothing, but wind resistance is with you all the way.  The T@b's streamlined shape is a great benefit, as would be with a low wind resistance tow vehicle.  Lift kits work against you, for example.  Keep added gear out of the airstream if possible.

Doug K

CrabTab

If you have a 320, a full freshwater tank will add about 5LB to the tongue weight. Here is a link to a discussion where I posted data with this info...

What (I Think) I've Learned About Tongue Weight on a 320 (vanillacommunity.com)

We always filled our freshwater tank at home to start a trip. This gave us some water to use, from a known source, while travelling to our destination. 

Jay_and_Kat

I suppose I should've specified, we're going to be getting a 400BD (build date is 7-Mar, so...)
The places so far we're planning to camp this summer don't have water hookups we could fill at, and the driving to get there is going to be comparatively flat or mild hills, so I'm thinking we'll fill up at home and take the hit on gas mileage.

As well as keeping an eye on our overall GCWR...

Horigan

We typically just fill at home before we go. I frankly can't tell the difference towing whether the tank is full or empty.  

Denny16

Jay, fill,up,at home before you leave, the weight will not make much difference in mileage once you get going, it only takes more energy to get it moving from a dead stop, once underway, miliage should be about the same, especially in flat landscapes.  Going up steep hills, weight will again make a difference, but as Kottum pointed out, wind drag is a bigger factor in MPG loss.  Filling up at home, gives you water you know is good to use.
 Cheers 

Bayliss

@Jay_and_Kat, I agree with the comments by @CrabTab and @Horigan.

I fill both the fresh water tank and Alde hot water tank (assuming I want hot water) before heading out on a trip, especially when there is no water readily available where I will be camping (e.g., boondocking.)  I also pressurize (fill) the water lines and prime the water pump so I don't have to use battery power at camp to accomplish that.  The best way to fill the Alde tank and pressurize the water lines is to connect a water hose between your house and trailer, turn on the water at the house spigot, and then partially/slightly open the trailer's hot and cold water faucets at the sink to get the air out of the water lines.  They will initially "sputter" quite a bit while expelling air and water, so be prepared for that.  You should also briefly operate the toilet valve to get the air out of that line.  You can do the same for the shower if you plan to use it.

P.S.  When attaching a fresh water hose to your trailer, whether at home or at a campground with hookups, don't forget to include a 40-50 PSI (max) water pressure regulator between the trailer water connection inlet and the hose.

CrabTab

As usual, @Bayliss has the most thoughtful answer!

Marceline

For any clamshell owners who stumble across this post in the future...
If you have an early clamshell model the water tank may be located in the galley at the back, in which case it is better to travel with an empty tank. The extra weight of a full water tank so far behind the axle could induce sway. 

pthomas745

If you are camping anywhere in the west, in the worst drought in years...carry water.  

N7SHG_Ham

Always go full with our 400, never know where you can fill or quality. On the 400, and I suspect 320 the weight is over the axle, it actually probably tows better than empty.

Best way to increase fuel economy is a light right foot and slowing down. Just read an article today that said over 50 MPH, wind is biggest affect on economy and every MPH over 55 drops fuel economy 0.1 MPG, so 65 vs 55 will drop you one MPG. If you were getting huge numbers towing, that is probably insignificant, but at 15 MPG, that is seven percent worse fuel economy. 70 vs 55 drops fuel economy about 10%. At price of fuel today it adds up, slow down, enjoy the ride and save some $$.

Roamy400

We always start out loaded with water and everything purged so we don't waste water when we get where we are going. We also tend to stop and use the camper bathroom along the route sometimes if we don't feel like finding a place to go in. Just makes it easier for us. Ina 3 day trip we have not had any issues with running out of fresh or filling black and gray above about 3/4.

Slackers

We're now in the camp that fills the tank ahead of departure. It's nice to have water on board for bathroom stops along the way.  It's also insurance should there not be water at your destination (for unanticipated reasons).