An over the wheel well liquid storage tank for storing liquid in a bed of a truck includes a tank body having a main tank portion shaped to fit in an area adjacent a wheel well in the bed of a truck and an over a wheel well tank portion shaped to fit in an area above a wheel well in the bed of a truck. The main tank portion is shaped to fit in an area adjacent a proximal side of the wheel well or in an area adjacent a distal side of the wheel well. A mounting system is coupled to the tank body. The mounting system couples the tank body to the bed of a truck. The mounting system includes a channel coupled to the tank body and a mounting bracket for coupling to the channel and to the truck. The mounting system includes an adjustable bumper.