These water detection and flood prevention systems feature automatic water shut off valves that connect at the main water supply line for your home or business. One or more water leak sensors are placed anywhere water could potentially leak, and they will signal the main water shut off valve automatically as soon as a leak is detected. Some systems also have an output to connect to a dialer, security or automation system when a leak is detected to provide an alert or other actions as well as automatically shutting off the water valve. Start with a main actuator and valve, and add as many wireless sensors as needed. Or choose from one of our automatic water shut off starter kits.