Step 1 PARTS
1) battery & connector
4) 5 Led
5) 16v condensor
6) 330ohm resistor
Now you can take help with circuit diagram if you can't able to understand then you can ask me
The positive terminal of the wire is to be connected with all led's and the another terminal of the battery should be dipped in water at the base of tank. now connect wires with the LED saperetly and connect the last led with buzzer also dipp the wires in the water tank.
Step 2: How It Works
when the nagetive charged wire comes in the contact of water the charge flow in the water.
when water rises up it come in the contact of the wire and circuit gets completed and the first led glow and when it comes in the contact of the last wire the Led starts glowing and the buzzer starts buzzering.