20 gallons at a pint a pound adds a considerable amount of weight so B careful you don't get your rig out of balance. 8LB X 20 = 160LB.
I thought I'd posted this earlier, but, yes, weight
is an issue when you add water capacity. I'm the guy who remodeled his Scamp
to have a rear bench seat with a 20 gallon water tank underneath, and it's good to point out that my Scamp
is a 5th wheel trailer with a hitch weight of seven-hundred pounds, give or take another hundred.
It's pretty normal for 5th wheels to have 25% of the trailer weight sitting on the hitch, and that gives 5th wheel owners a lot of latitude in how they load and distribute the weight of their trailer.
That's not true with conventional-hitch trailers. Conventional hitch trailers should put 10 to 15 percent of their trailer weight on the hitch; that's 200-300 pounds for a 2000 pound trailer. Throw 20 gallons of water in the back of your trailer and you'll substantially reduce the tongue weight, which can cause unsafe sway at freeway speeds.
If you gotta have more water and you're not a 5th wheel owner, consider carrying a few jerry cans in the back of your vehicle. That way you won't unbalance your tow, and you won't have to move your trailer when you need to refill the tanks. If you're not comfortable lifting a full jerry can, consider getting a transfer pump; I've seen transfer pumps that can move a gallon of water in three or four (energetic) strokes.
It's also worth noting that, because some of the tank's capacity is "dead space" (the output and overflow/fill fittings are not right at the bottom and top of the tank) Scamp's "10 gallon" tank holds something closer to 8-1/2 usable gallons. Three 3-gallon jerry cans will double your water capacity.
One last "capacity" comment before I go. Fresh water capacity is one thing, grey and black water capacity is another. Our Scamp 5er has a 27 gallon grey waste tank, and our "20 gallon" capacity fresh tank holds 17 usable gallons of water. Some of the fresh water does go down the toilet and into the black tank, but, even so, if we fully topped our empty fresh water tank when it ran dry we would overflow our gray water tank before it ran dry a second time. We can only "top up" the fresh tank once before that happens, and even then we can't completely refill the tank.