Here is a tested Arduino project that uses 3 sensor probes as water level indicator with 3 leds and one LCD display + a simple controller that turns on a motor when the water has reached the desired ...

The XBee can detect the water level by testing for a closed circuit between the two electrodes of any sensor module. The water acts as a sort of switch that closes the circuit.

It runs on an Arduino MEGA 2560 PRO (or similar microcontroller) and supports a wide array of additional hardware including pressure transducer, water level sensor, flow meter, OLED display, and more.