Method for water saving by retrofitting an institutional plumbing fixture and plumbing fixture made by such method

A modular retrofit device that is inserted into an aperture cut in a sidewall of an institutional plumbing fixture, the institutional plumbing fixture having a plurality of sidewalls, a combination of an integral lavatory basin above the sidewalls, and a toilet bowl integrally attached to one of the sidewalls below the lavatory basin, wherein the lavatory basin includes a drain pipe for draining water into a drain trap provided for the plumbing fixture, the drain pipe having a portion cut out between the lavatory and the drain trap to yield an upper opening of the drain pipe and a lower opening of the drain pipe between which the modular retrofit device is inserted, the modular retrofit device comprising:

• a urinal-type collection receptacle that is shaped and dimensioned to fit into the aperture cut in the sidewall of the institutional plumbing fixture to receive the modular retrofit device as an insert that is retrofit into the institutional plumbing fixture to redirect water used to wash a user's hands to flush the urinal-type collection receptacle and thereby save water;
• a water inlet opening on a top side of the urinal-type collection receptacle, wherein the water inlet opening including a first connecting stub (32) that connects the water inlet opening of the urinal-type collection receptacle to the upper opening of the drain pipe such that water draining from the lavatory is received through the water inlet opening;
• a water outlet opening on a bottom side of the urinal-type collection receptacle, wherein the water outlet opening includes a second connecting stub (34) that connects the water outlet opening of the urinal-type collection receptacle to the lower opening of the drain trap of the institutional plumbing fixture;
• wherein, upon insertion of the modular retrofit device into the aperture of the institutional plumbing fixture, a continuous, open flow channel is established to redirect water used by the user to wash the user's hands after urinating in the plumbing fixture from the lavatory basin, down through the upper opening of the drain pipe, into the water inlet opening, then through and across an interior of the urinal-type collection receptacle, out through the water outlet opening, then down through the lower opening of the drain pipe, wherein water from hand washing after urination into the urinal-type collection receptacle serves to flush down the receptacle, without necessitating flushing of the toilet bowl, thereby saving amounts of water otherwise used in flushing of the institutional plumbing fixture.