Abstract: A water level sensing probe having a probe body (24), a protective sleeve (28), and an external housing (26) is disclosed. The body contains a detector board (40) that partially protrudes from its bottom and a logic board (42) that partially protrudes from its top. The detector board senses the level of electrically conductive fluid and transmits an indication of that level to the logic board that controls the operation and partially processes the data in response to commands received through a cable (28). The detector board is protected by the protective sleeve (28) while the logic board is enclosed in the external housing (26). The probe is used by positioning on the bottom of a fluid containing tank or other vessel. Water at the bottom of the tank forms a bridging contact between a ground plane and a number of traces on the detector board proportional to the level of the water.