Abstract: An apparatus for sensing the presence of a conductive fluid on an upwardly facing generally planar surface of a floor, and a method of installation thereof. The apparatus includes an electrically insulating base dimensioned for installation under the floor such that the upwardly facing generally planar surface is maintained generally planar upon completion of the installation, The apparatus further includes first and second sensing conductors connected to the base and extending therefrom in generally parallel, spaced apart relation and being operable to be inserted into respective openings extending through the floor from a base contacting surface of the floor to the upwardly facing generally planar surface. Conductive fluid on the upwardly facing generally planar surface, in contact with and between the first and second conductors, is operable to conduct an electric current supplied by a sensing circuit connected to the first and second conductors.