The Plumbing Manufacturers Institute participated in the signing of a Memorandum of Understanding in a ceremony held in Washington, DC, Jan. 6, at the offices of Environmental Protection Agency Administrator Stephen Johnson.  PMI will partner with four other plumbing organizations - Plumbing Heating and Cooling Contractors, the International Association of Plumbing and Mechanical Officials, the International Code Council and the Alliance for Water Efficiency - to share research on water efficiency.