This practical module can sense the presence of water. It is non-contact because there is no sensing element that makes physical contact with the water. The sensor is even able to detect the presence of water through small thicknesses of plastic, glass, ceramic and other non-metallic materials. The sensor has a built-in red indicator LED that lights up when water is detected, and the detection signal emits a high-pitched signal when water is present. The polarity of the detection signal can be changed by earthing the black wire, which changes the detection signal type to an active low signal. The sensitivity of the sensor can be adjusted by opening the top cover and turning the blue potentiometer.