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Meet the Minds: Paula Kehoe on Pioneering Onsite Water Reuse in Cities

San Francisco has helped lead the way in the use of onsite non-potable water systems that can supplement drinking water supplies, explains Paula Kehoe, director of water resources for the San Francisco Public Utilities Commission.

Written by Tara Lohan Published on Read time Approx. 4 minutes
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Plants along a city sidewalk are part of an onsite non-potable water reuse system at the San Francisco Public Utilities Commission's headquarters in San Francisco, Calif.Tara Lohan

In a state with periodic droughts that are expected to increase in severity, California water suppliers know they must make the most of drinking-water supplies. For some that means increasing conservation; for others, it means developing alternative water sources. San Francisco has done both. Residents have some of the lowest per capita water use in the state, and the city’s water supplier, the San Francisco Public Utilities Commission (SFPUC), has been a leader in pioneering the use of onsite non-potable water reuse systems that can take advantage of water sources such as stormwater, rainwater and graywater.

SFPUC incorporated an onsite water treatment system into its own building that along with rainwater catchment, saves 65 percent of the building’s potable water. The agency also developed a program, spearheaded by SFPUC’s director of water resources, Paula Kehoe, to aid developers in using onsite treatments systems for non-potable water. The success of the program led to the creation of an ordinance in 2015 requiring new developments of more than 250,000 square feet to use onsite water treatment systems for non-potable water uses like toilet and urinal flushing.

As part of our Meet the Minds series with water experts, we talked to Kehoe about how San Francisco has collaborated with other communities across the country to advance onsite water reuse, and how SFPUC is focusing on water and energy resilience.

Water Deeply: What are you working on that you want the world to know about?

Paula Kehoe: Similar to many communities in California, the SFPUC is diversifying its water supply portfolio by implementing a number of recycled water, groundwater and conservation programs. We are also pioneering new ways to collect and treat water for reuse within buildings and neighborhoods in San Francisco.

We recognize the opportunity to build upon our centralized water infrastructure by integrating smaller, onsite water treatment systems to produce water fit for toilet flushing and irrigation that not only matches the right resource to the right use, but also helps us stretch our drinking water supplies. These onsite non-potable water systems that collect and treat rainwater, stormwater, graywater, blackwater and foundation drainage will begin to transform the way we live and do business in San Francisco.

Water Deeply: What surprised you in the past year about work in the water field?

Kehoe: This paradigm shift with the focus on collecting and treating various sources of water onsite for non-potable uses is not just a San Francisco trend. The number of communities across North America who are eager and interested in integrating onsite non-potable water systems to develop local water supplies and strengthen the resiliency of water infrastructure is increasing.

Last year, we established the National Blue Ribbon Commission for Onsite Non-potable Water Systems. Our partners include public health agencies and water utilities from Hawaii, Southern California, the Pacific Northwest, Minnesota, Texas, Colorado, Arizona, Washington, D.C., and New York. Over the next two years, we plan to develop new business models for utilities, craft state model guidance and policies, and prepare best management practices to support local implementation of onsite non-potable water systems.

Our work is driven by risk-based science and research and is supported by the U.S. Water Alliance and Water Environment & Research Foundation.

Water Deeply: Who/what do you find most inspiring in your field?

Kehoe: We are surrounded by inspiration. In San Francisco, our residents embrace conservation as a way of life, using just 41 gallons [155 liters] per person per day. We are seeing new green buildings and developments in the city installing onsite water systems to further reduce their water footprint.

Some of the best minds in the Bay Area are working on innovative technologies that will enable us to use and reuse water more efficiently. Across the nation, many utilities are embracing a One Water approach to address water challenges. In San Francisco, our recent adoption of OneWaterSF builds upon many years of developing innovative programs to manage water and establishes our approach to optimize our finite water and energy resources to balance community and ecosystem needs.

Water Deeply: What’s the most important thing California should be doing right now to create a sustainable water future?

Kehoe: Encourage new ways of thinking and create innovative approaches to provide greater water and energy resiliency. Fostering innovation takes work and requires us to recognize that we have many solutions to our water challenges. This being said, we need to honor local context to adapt our water management strategies to our communities and avoid the one-size-fits-all approach. It’s One Water, not One Size.

Water Deeply: Ten years from now, what do you hope California will have accomplished on water issues?

Kehoe: A cultural shift in that we value bio-solids, wastewater and bio-gas by placing a value on these resources as much as we value our drinking-water supplies today. Ideally, cost-effective and energy-efficient resource recovery facilities of various sizes and scales are commonplace in California.

READ MORE IN OUR MEET THE MINDS SERIES

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