Abstract: Decontamination systems, and methods of their use, for decontaminating boats of noxious marine life when the boat is pulled out of the water. The system is generally located at a boat launch site. Decontaminating water sprayed on the boat falls onto the ground, and runs along the surface back into the body of water. The system includes a water pump, a water intake line which extends, from the pump inlet port into the body of water. An outlet line extends from the pump outlet port to a spray nozzle. The spray nozzle sprays pressurized water onto the outside of the boat. The impact of the water removes unwanted marine life from the boat. After decontamination, the boat can be taken to a different body of water with little, if any, risk of infecting the different body of water with marine life from the first body of water.