Managing Risks in Water Reuse: Intersection of Policy and Science


  • Mary E. Sadler PE, Benjamin Stanford PhD - Hazen and Sawyer

The US is currently experiencing an evolution in our understanding and application of direct potable reuse (DPR) and indirect potable reuse (IPR). Currently non-potable and potable reuse regulation is under the jurisdiction of individual states. Federal regulations do not govern the quality or quantity of reclaimed water but the EPA has published technical guidance on reuse practices in an attempt to aid states that do not have reuse regulations or require assistance. EPA does not currently have a plan for applying federal regulations to water reuse and is likely to continue to defer to states and the existing federal SDWA regulations to protect human health.

Most states require non-potable reclaimed water to be treated to acceptable standards for suspended solids, bacteria, and organic content, depending on the end use of the water generally defined by two or more categories in each state. IPR, on the other hand, is the intentional augmentation of a drinking water source with purified recycled water followed by an environmental buffer that precedes drinking water treatment and is currently regulated in only a few states included Virginia on a case-by-case basis. DPR is the introduction of purified water directly into a drinking water plant (with or without raw water supply blending) or directly into a water distribution system, is currently practiced in Texas, on the books in NC and OK, soon to be regulated in CA, yet is specifically prohibited in VA. Both IPR and DPR applications typically require a higher water quality based on policy and public health protection, even if prescriptive technology requirements are not mandated by regulation.

This paper will discuss the rapidly evolving regulatory requirements for IPR and DPR across the U.S., the various definitions of reuse terminology and application, and the risks associated with the range of these regulated approaches.

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