Here is the schematic of a water level alarm circuit. The circuit will work as a water level sensor and will give a melodious alarm sound when the two probes in the circuit will detect water. You can use this water level indicator circuit to detect the level of water in any place for example in swimming pool,
water tank etc. The melody circuit is build around the famous CMOS Melody IC UM66 comes in TO-92 transistor package.
For using the circuit simply attach the two probes on the desired level of water on which you want the indication and make two to three inches gap between the two probes.