Stormwater and Resiliency: How San Francisco’s Stormwater Management Ordinance is Spurring Non-Potable Reuse
In 2010, the San Francisco Public Utilities Commission (SFPUC) enacted a Stormwater Management Ordinance which requires projects that disturb 5,000 square feet or more of ground surface to manage the stormwater that falls on their site. With most sites located in the combined sewer area and required to reduce both the runoff rate and volume, many are capturing and reusing stormwater to meet this local requirement. Over 40 stormwater reuse systems are either in operation or planned within the City. Installations can be found in every type of facility including grocery stores, affordable housing developments, homeless shelters, high rise apartment buildings, mixed use developments, and municipal buildings.
This presentation will highlight how San Francisco’s stormwater requirements are spurring new and redevelopment to not only capture and reuse stormwater, but to also integrate alternative water sources such as greywater and foundation drainage to develop higher potable water offsets resulting in more cost effective installations. Case studies will highlight innovative approaches to stormwater capture and reuse in both built and planned projects in San Francisco’s dense urban landscape.
This presentation reviews the SFPUC’s Urban Watershed Management Program efforts to encourage and require projects to incorporate onsite stormwater reuse including potable water offset achievements and other strategies that increase San Francisco resiliency to drought, climate change and a growing population.
Onsite stormwater reuse reduces demand on San Francisco’s water and wastewater systems through reduced water supply demand and wastewater discharge while also mitigating peak stormwater flows that can lead to combined sewer discharge events during large storms.
San Francisco recognizes that water reuse is a reliable, local water supply that reduces vulnerability to droughts and that to ensure safe and effective installation and operation of non-potable reuse system, city-wide guidance was needed. So in 2012, the City of San Francisco adopted the Onsite Water Reuse for Commercial, Multi-family, and Mixed Use Development Ordinance. Commonly known as the Non-potable Water Ordinance, this program allows for the collection, treatment, and use of alternate water sources for non-potable applications and provides guidance for on-going monitoring, reporting and inspection. This presentation will provide an overview of this unique local guidance and a summary of current policy efforts related to non-potable reuse.
Engineers and designers will learn about integrated reuse design approaches that meet local stormwater requirements while also reducing potable water demands. State and municipal representatives will learn about policy efforts to ensure the safe installation and operation of these systems.
While stormwater regulation is currently the primary driver for San Francisco’s stormwater reuse projects, California’s drought is creating urgency for the implementation of non-potable reuse systems with substantial potable water offsets. If the drought continues and water conservation requirements become more restrictive, water resource professionals need cost-effective non-potable reuse solutions. This presentation will detail how stormwater reuse is making a difference in the City of San Francisco and how other communities can learn from their efforts.