Abstract: A resistive liquid detection and shut-off system is used to protect a floor area from water damage. An elongated sensor comprising a flexible plastic tape with an adhesive backing and a pair of conductive metal strips detects liquid drips, flows and trickles, but not liquid beads. A detection circuit measures resistivity changes in the sensor, and an output circuit activates a solenoid-operated water shut-off valve in response to predetermined resistivity changes in the sensor. A connector comprising a body of electrically insulating material with electrical terminals thereon connects portions of the elongated sensor together so that they can have any length and relative position. A battery may provide the power for the entire system, with a battery voltage monitoring circuit also provided.