Plumbing Efficiency Research Coalition

The Plumbing Efficiency Research Coalition (PERC) was formed on January 6, 2009 when five prominent organizations signed a historic Memorandum of Understanding (MOU). The MOU created a collaborative network to advance plumbing research initiatives pertaining to water efficiency.

The coalition also endeavors to identify possible unintended consequences of water efficiency and, through applied research, determine best design and maintenance practices for the safe use of water in buildings.

The signatories included the Alliance for Water Efficiency, the International Association of Plumbing and Mechanical Officials, the International Code Council, the Plumbing-Heating-Cooling Contractors—National Association, and the Plumbing Manufacturers International. The American Society of Plumbing Engineers joined PERC on February 22, 2011.

Since its formation, the coalition has conducted extensive research in the area of drainline transport of solid waste in building drains. The reports below are intended to provide guidance to plumbing engineers, water utilities, manufacturers, facility managers, building owners, efficiency experts and code officials.


November, 2012 – PERC releases long-anticipated results of Drainline Transport Study – Download the Phase 1 report here.


August, 2014 – PERC launches Phase 2 of the Drainline Transport Study, building upon the results of its successful Phase 1 report The Drainline Transport of Solid Waste in Buildings. Read the Phase 2 Work Plan. The first project selected was the drainline transport of solid waste in buildings


September, 2015 – PERC releases the report on Phase 2.0 of the Drainline Transport Study. Updated April, 2016 – PERC updates Phase 2.0 of the report with the addition of the Phase 2.1 Supplement.