It's a rare day when we travel with much of anything in the tanks. It all =s weight, which =s even worse fuel mileage. Water weight 8.3# per gallon, so just do the math x the number of tanks. If you're in a spot where it's impossible to dump, many of the state roadside rest stops have dumps and there's a sign posted to that effect. Watch for Pilot/Flying J truck stops or Love's. They usually have dump stations. If you just walk in and ask about dumping, they will usually tell you it's $x, but if you invest in a coke or some snacks and then ask, most often the price is $0.
