Saturation Study of Non-Efficient Water Closets in Key States

April 18, 2017
saturation study cover

Water-efficient toilets could potentially save up to 170 billion potable gallons of water per year across five states facing water scarcity, according to new research released today by the Alliance for Water Efficiency (AWE) and Plumbing Manufacturers International (PMI).

The “Saturation Study of Non-Efficient Water Closets in Key States” focused on Arizona, California, Colorado, Georgia and Texas – all five states have either experienced or are on the verge of experiencing significant shortages. The savings projected by the study (170 billion gallons of potable water yearly or 465 million gallons saved per day) could be achieved if non-efficient toilets in residential properties are replaced with water-efficient ones. This five-state savings can be extrapolated to an estimate of up to 360 billion potable gallons of water per year saved nationally.

This research produces important direction for water managers nationwide, as 40 out of 50 states anticipate water shortages in the coming years, according to a Government Accountability Office survey of state water managers published in 2013, with most of these states already experiencing periodic shortages. The five states researched represent 28% of the national population and 47% of all housing units in 2015, so the report examines a large part of the residential water consumption in the United States. Toilet flushing is the largest single indoor use of water, representing 24% of total use in single-family homes. Replacing non-efficient toilets with efficient ones is an important strategy to stretch available water supplies.

The AWE/PMI study demonstrates that current plumbing technology can make a tremendous water-saving impact, especially if toilet replacement programs can be accelerated. At the current 4% annual toilet replacement rate, the potential savings illustrated in this study will not occur for another 15 to 30 years unless replacement programs are accelerated.