Dec. 16, 2015 New NAS Report Addresses Uses for Graywater and Stormwater in Local Communities

Using Graywater and Stormwater to Enhance Local Water Supplies: An Assessment of Risks, Costs and Benefits.

Today, the National Academy of Sciences released a new report entitled, Using Graywater and Stormwater to Enhance Local Water Supplies: An Assessment of Risks, Costs and Benefits.

Much of the United States faces chronic or episodic water shortages. As detailed in this report, increased attention to the use of stormwater and graywater has been driven by factors forcing change in the design and management of urban water supplies and infrastructure. The National Academies of Sciences, Engineering, and Medicine’s Water Science and Technology Board initiated a study on the beneficial use of stormwater and graywater.

In the report preface, the study authors say, “The concept of a re-imagined urban water infrastructure—variously termed low-impact design, blue-green city, or water sensitive city— embraces sustainable practices in which metropolitan regions could serve as water supply catchments, provide ecosystem services, and prioritize livability, sustainability, and resilience. However, realizing this vision raises questions on exactly how graywater and urban stormwater should be captured, stored, and used. Because of the absence of ample documentation of costs, performance, and risks, many utilities are hesitant to integrate the practices into their long-term water resource plans beyond the simplest applications. Potential public health risks from microbial or chemical contamination associated with graywater or stormwater use raise concerns about safety, regulation, and management. To better address these challenges, the Academies formed a committee to study the risks, costs, and benefits of stormwater and graywater use to augment and conserve existing water supplies.”

This study was supported with funding from the Environmental Protection Agency Office of Water and Office of Research and Development; National Science Foundation; Water

Research Foundation; Water Environment Research Foundation; Los Angeles Department of Water and Power; WateReuse; City of Madison, Wisconsin; National Water Research Institute;

and the National Academies’ President’s fund.

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