Advancing Water Reuse in the Bay Area: Integrating Water Reuse into a Regional Approach to Water Management

This report provides a summary and synthesis of the Bay Area One Water Network’s workshop on advancing water reuse across the San Francisco Bay Area, held December 17-18, 2019 in Berkeley, California. The workshop brought together a diverse group of professionals representing drinking water and wastewater utilities, businesses, regulatory agencies, non-profits, and academia to discuss ways in which water reuse could be integrated into a regional approach to water management in the Bay Area.

With the prospect of more severe droughts in California’s future, and other stresses on urban water, Bay Area water managers are seeking cost-effective solutions to enhance the resilience and sustainability of their water supplies while also maintaining ecosystem health. Water reuse, both for potable and non-potable purposes, is one potential water source that can help diversify the region’s water supply portfolio. There is broad interest in water reuse across the state and the nation. In the Bay Area, water managers and other stakeholders are interested in water reuse because it can allow for appropriate use of critical water resources, provide environmental benefit by reducing the region’s demand for imported water, efficiently meet regulations on wastewater discharge, and burnish a “green” reputation for the implementing organization. A regional approach to water reuse can ensure the coordination and cooperation necessary for planning and implementing water reuse projects, enhance opportunities for funding, and allow water managers to make informed decisions about site-specific opportunities for water reuse. Having plans for water reuse prepared in advance can facilitate action on water reuse projects when opportunities for funding are available.

Workshop participants considered four opportunities for water reuse in the Bay Area, all of which are likely to play a role in the region’s future: 1. Centralized non-potable reuse (i.e., for irrigation, shoreline resilience in nature-based solutions like horizontal levees, and industrial uses); 2. Onsite and community-scale non-potable reuse (i.e., for landscape irrigation, cooling, and toilet flushing); 3. Graywater reuse (i.e., household-scale use of laundry and shower water for landscape irrigation); 4. Potable water reuse (i.e., groundwater recharge, reservoir augmentation, and direct potable reuse).

As workshop participants discussed local experiences and opportunities, it became evident that advancing water reuse in the Bay Area depends upon addressing specific gaps and barriers in the region. To advance water reuse, the Bay Area can:
• Improve institutional support
• Evaluate regulatory action
• Develop collective financial capacity
• Conduct research to address data gaps
• Standardize communication strategies
• Jointly support both centralized and onsite water reuse systems that provide multiple benefits and drive innovation