A water level detection system in a pool, spa, fountain or water feature forming a body of water within, the water level detection system is provided with a tap line coupled to a plumbing line on a suction or supply side of a filtration system and admitting water from the pool, spa, fountain or water feature such that the change in level of the water in the tap line corresponds to a change in level of the water in the pool, spa, fountain or water feature. A sensing module is mounted to the tap line and has at least one sensor for detecting the height of a column of water or the pressure of a column of air in the water tap line. A controller is coupled to the sensing module and adapted to collect the data from the sensors that detect changes in the level of the water level of the body of water, communicate the detection of such a change, and report such a change to initiate addition or removal of water from the body of water to adjust the water level in the body of water to a set point.