In drag racing, the wet area used to help start a burnout is called the water box.
Track workers wet this short section before the starting line so a car’s driven tires can break traction easily. The driver rolls into the water, spins the tires, and builds heat before backing toward the staging beams. The procedure also helps clean dust and debris from the racing surface of the tires.
The water box has an older and more hazardous predecessor: the bleach box. Early drag racers used bleach and other substances to make the tires spin, but flammable traction compounds could create spectacular fire burnouts. Water became the standard because it provides the necessary lubrication without the same fire risk.
The water box should not be confused with the shutdown area, return road, or staging lane. Those are different parts of a dragstrip. The shutdown area gives the car room to slow after the finish, while the staging lane is where cars wait before approaching the starting line.