It's a shame no one still uses the terms 1/2 ton pickup, 3/4 ton or 1 ton pickup. People might better understand what they are buying.
On the other hand the guy probably didn't know 250 gallons of water weighs 2083lbs even if he knew the load rating of his truck.
A guy near me put 2 tanks on a standard 8ft light-duty trailer. He never even made it to the paved road, pulled his bumper off.