Stormwater Runoff Charge

Client

San Francisco Public Utilities Commission (SFPUC)

Location

San Francisco, CA

Project Description

San Francisco is the only coastal city in California served by a combined sewer system that collects, conveys, and treats both stormwater runoff and sanitary sewer. SRT worked with the San Francisco Public Utilities Commission (SFPUC) to design a rate structure and credit program that equitably charges customers for the stormwater runoff from their property while providing real incentives to property owners and developers to build green infrastructure. SRT provided critical analysis and recommendations on financial, technical, administrative, and implementation considerations that drove the final program design. The final rate design established a tiered flat rate for residential parcels based on the average permeable and impermeable areas of all parcels in each tier, and a standard charge based on a parcel’s actual permeable and impermeable area that applies to all other customers.

We facilitated communication and collaboration among multiple departments to build the organizational infrastructure for charge implementation. We also utilized GIS to develop a map of areas within the city that are excluded from the stormwater runoff charge because they are either located in an area with separate sewer systems or the stormwater runoff drains to a body of water. The result was a program that met SFPUC’s policy goals, minimized the administrative burden for staff, and was easy for customers to understand. The charge ultimately contributes to a more resilient wastewater system through increased capture of stormwater at the parcel level and by accurately allocating the cost of managing stormwater runoff.

Unique Challenges

Every aspect of the program demanded nuanced analysis to ensure that it is easy for customers to understand, meets SFPUC’s policy goals, minimizes administrative burden for staff, and complies with Prop 218. Determining the criteria for the flat residential rate and thresholds for each tier required evaluating the size and characteristics of all parcels with residential service accounts in the city and creating a calculator to test the financial impact of various tiering options. Creating a credit program that provides customers with bill reductions for installing green infrastructure required defining criteria for staff and customers to easily assess whether the green infrastructure is meaningfully reducing the stormwater runoff entering the combined system and how to value that reduction.

Value Added By SRT

SRT’s facilitation process and technical know-how creates a smooth and illuminating upgrade for the diverse stakeholders of this project, empowering them to move forward with the potent and workable tools we created. We dialed in efficient, customer-friendly frameworks for capturing and measuring stormwater runoff, including building a calculator for customers installing stormwater management infrastructure. We contributed a robust toolset for SFPUC to manage and navigate changes in their stormwater and wastewater system programs.