This circuit is very sensitive to trigger and activate the audio visual alarm when wetness is sensed at its probes. This project is useful at homes to detect the water [[wysiwyg_imageupload::]]supply in the situations when the timing of water supply is not fixed. This circuit uses the 555 timer along with some sensor element which can detect moisture.In this circuit based project, 555 timer works in astable mode. It is driven by the emitter current which is coming from BC548 transistor as this transistor has high gain. In astable mode IC 555 functions as an oscillator. So for 555 to work in full oscillator mode a high current is required so as to trigger it. As the probes sense the moisture on it, the transistor gets switched ON and small current starts flowing between the base and the emitter. When no moisture is detected i.e. in dry state it remains OFF.