Nothing when its a little, but when its 3inches and I don't even have people or gear in the back lol.
Also Moomadaze I think you asked about the bed cover? Hasn't leaked a drop. Worked perfectly and my mileage seems to be getting better, been getting 18 pretty consistently since I installed it. Might be the fact the rear of the truck is higher then the front now by 1 inch like factory.