The sensor is installed on the tile line of the pool. The sensor is connected to the control unit via a waterproof cable. The standard length of the cable is 24 feet. The sensor cable may be "spliced".

Water enters the sensor chamber through the holes on the front and side of the sensor. The system adds water to the pool until the water reaches the "ideal" level on the sensor. If the system has the "dump" function, water is removed from the pool until the level is below the "ideal" level on the sensor.

The system compares the electronic sensor outputs and determines which are dry and which are wet, thus determining the water level. The sensors are not metal plates or rods. The sensor is not affected by chemicals, water evaporation or water residue.

The sensor is not affected by temporary changes in pool water level due to bather load or other temporary changes. Wave action due to swimmers does not affect the sensor.