Plumbing Manufacturers International (PMI) has introduced parameters for the use of indoor recycled water. Developed for the benefit of water utilities to ensure that plumbing products function as intended by manufacturers, the water quality limits provide recommended ranges on 13 different parameters of water quality.

“This guidance will help water utilities to produce recycled water that will not hamper the performance of residential and commercial plumbing products that can be used with nonpotable water, such as toilets and urinals,” PMI CEO and Executive Director Kerry Stackpole said.

Scientists, engineers and technical experts among PMI member companies working on PMI’s Sustainability Task Group collaborated on the guidance.

Water districts may choose to use recycled water — also known as reclaimed water or treated wastewater — within their jurisdictions for uses that do not require potable water, such as irrigation, power plant cooling, or toilet or urinal flushing. However, in the absence of federal standards for the use of this water, “water utilities are adopting various requirements and guidelines, and PMI’s goal is to provide guidance on recycled water from a manufacturing perspective,” Stackpole said.

PMI urges caution until further research is completed

PMI’s action was spurred by its experience last year in California, where it worked as part of a coalition to place a hold on a mandate for the indoor use of recycled water in newly constructed residential and commercial buildings.

“We were concerned about the lack of scientific research into the use of recycled water indoors and urged regulators to wait until a better understanding of the potential benefits and risks could be determined,” Stackpole said.

Virginia Tech engineering professor Marc Edwards is currently conducting a study on the public health ramifications of indoor recycled water use with funding from the American Water Works Association and National Science Foundation.

Pushes for the increased use of recycled water will likely surface again, and PMI Technical Director Matt Sigler said the new parameters and ranges reflect the time PMI members have had to prepare.

“We’ll continue being proactive, coordinating with our members on research efforts, and fully vetting all concerns surrounding public health and safety and product performance,” Sigler said.

He added that PMI’s recycled water parameters are not intended to serve as guidance for public health and safety and are not intended for plumbing products used for bathing, cooking, drinking or hygiene purposes (e.g., faucets, shower heads, personal hygiene devices and bidets). 

View PMI's recommended parameters for indoor use of recycled water here.