Used my Sovereign to pull my dad's water wagon over to the show grounds, fill it up and put it where they use it. Did some calculations and it holds over 400 gallons, and while not filled to the rim I think with the weight of itself and the water 4,500lbs is a good estimate. Started losing traction on a muddy uphill portion but it did a fine job. Took 25 minutes to fill it, during which my boy made himself comfortable.