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 ...

Non-contact technologies and regional regulatory demands drive industry growth Level Sensors & Switches Market Level Sensors ...

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.

FloSenso - India's no. 1 App based Automatic Water Level Controller for Smart Homes launched by EnergyBots. Automatic water pump operation to prevent overflow & water shortage ...

On cost, he says compared to the cost of submersible motor starter pump and automatic water level controller, his device costs less than 40 %. Besides, any electrician can service it.