Executive Management

Dennis Herrera is the General Manager of the San Francisco Public Utilities Commission (SFPUC), which provides retail drinking water, wastewater, and power services to the City and County of San Francisco. The agency also provides wholesale water to three other Bay Area counties. He provides leadership and management of the agency’s public policies and strategic initiatives, and oversees all assets, resources, and functions of the agency.

He joined the SFPUC in 2021 after serving as San Francisco City Attorney for nearly 20 years, where he built one of the premier public law offices in the country. As the SFPUC’s lawyer, Dennis was at the forefront of pivotal water, power and sewer issues facing San Francisco. He represented the agency before the Federal Energy Regulatory Commission, brought pioneering litigation to protect the SFPUC’s combined sewer and stormwater system from sea-level rise, and defeated a years-long attempt to drain Hetch Hetchy Reservoir.

Dennis earned his bachelor’s degree from Villanova University in Pennsylvania and his juris doctor from the George Washington University School of Law in Washington, D.C.

Ron Flynn is the Deputy General Manager and Chief Operating Officer of the San Francisco Public Utilities Commission. Appointed to this role in 2021, Ron works with the General Manager on all policy and strategic initiatives, oversees the agency’s daily operations, including the three utility enterprises, Water, Wastewater and Power, and the three bureaus, Infrastructure, Business Services, and Professional Services. He also supervises the agency’s Development, Emergency Planning & Security, and Government Affairs divisions. Prior to this position, Ron served for nearly 16 years in the San Francisco City Attorney’s Office under Dennis Herrera. During that time he served in many roles, including as Chief Deputy City Attorney, where he oversaw the City’s litigation teams, and worked closely with departments and agencies, including the SFPUC, on procurement, financial, and litigation matters. He worked on Hetch Hetchy litigation, PG&E’s bankruptcy, and other SFPUC-related issues. Ron previously served as Team Leader of the Construction and Public Contracting Team in the City Attorney’s Office, working on many SFPUC projects, including the Water System Improvement Program (WSIP). Ron is a Bay Area native who lives in San Francisco. He graduated from California Polytechnic State University, San Luis Obispo (B.Sc.), Harvard University (Ed.M.), and University of California, Berkeley School of Law (J.D.)

Marco Barker is the Chief Diversity, Equity, and Inclusion Officer responsible for collaborating across all enterprises and bureaus in advancing equitable and inclusive outcomes and cultural change and leading the Racial Equity, Diversity, and Inclusion team in high-profile projects, initiatives, and data analysis for capacity and community building.

Prior to the SFPUC, Marco served as the inaugural Vice Chancellor and Senior Diversity Officer at the University of Nebraska–Lincoln, where he led diversity, equity, and inclusion initiatives across the university’s 6,000 employees and 23,000 students. His other leadership experiences include roles at Westminster University, the University of North Carolina at Chapel Hill, and Louisiana State University. 

Marco has been recognized as a Utah Business Forty Under 40 honoree. His board and advisory service have included the Utah MLK Human Rights Commission, KeyBank Utah Advisory Board, the NCAA Board of Governors Committee to Promote Cultural Diversity and Equity, and the Lincoln Community Foundation. He is an inductee of the Arkansas Academy of Industrial Engineering and currently serves on the board of the American Association of Colleges and Universities.

Marco holds degrees from Louisiana State University (PhD in educational leadership), Webster University (MBA), and the University of Arkansas (BS in industrial engineering) and a certification in HR organizational development.  

Nancy L. Hom is the Chief Financial Officer and Assistant General Manager for Business Services, providing direction and oversight for the Financial Services, Audit, Loans & Grants, Customer Services, and Strategy Innovation & Change bureaus. She has led several important bureaus of Business Services, including serving as the Assurance & Internal Control Director for ten years; and more recent, as the SFPUC’s co-Deputy Chief Financial Officer. Nancy has over 20 years of experience leading financial and governance teams in public agencies and has invaluable knowledge of the City’s financial and accounting guidelines and systems, capital improvement projects, and regulatory requirements. Prior to joining the SFPUC, she was the Chief Financial Officer for the Department of Child Support Services and served as a leader in the Office of the Controller’s Budget and Analysis division.

Nancy earned her Bachelor of Science in Business Administration from San Francisco State University, concentrating in Finance, Internal Audit, and Project Management. She also maintains two professional certifications from the Institute of Internal Auditors as a Certified Internal Auditor and Certified Risk Management Assurance professional.

Jennifer S. Hopkins will serve as the Assistant General Manager and Chief Administrative Officer (CAO) for the Professional Services Bureau, effective July 1, 2026. The Professional Services Bureau is comprised of the Office of the CAO, Communications, Real Estate Services, Fleet Operations, Human Resources, Information Technology Services, Community Benefits and Facilities. For over 25 years, Jennifer has provided strategic leadership and direction to diverse teams like Professional Services, with the responsibility of creating a seamless support experience for those she served. Some of her accomplishments include delivering quality technical solutions, building client partnerships, creating high performance teams, launching new “Startup Divisions”, establishing formal vendor/contract management practices, developing community programs, investing in employee engagement, and leading organizational change and transformation projects. Jennifer joined the SFPUC in 2022 serving as the Department’s first Chief Information Officer. Prior to the SFPUC, Jennifer was an Executive Leader in Contra Costa County, the City of Fairfield, UC Berkeley, and the City of Kansas City Missouri. Jennifer holds a B.S. in Computer Science Information Systems from Jackson State University, a M.S. in Management from Baker University; she is a recognized Credentialed California County Technology Executive and completed the UC Berkeley Leadership Program Certification (MOR Associates).

Michael Hyams is the Acting Assistant General Manager of the Power Enterprise, where he oversees the operations of San Francisco’s electricity services, Hetchy Hetchy Power and CleanPowerSF. His professional background includes 20 years of service with the SFPUC’s Power Enterprise where he has held various positions.

Prior to being appointed to his current role, Michael served as Deputy Assistant General Manager, where he was responsible for overseeing CleanPowerSF operations and the Power Enterprise’s power supply resources. Michael led the Power Enterprise’s development of CleanPowerSF, San Francisco’s community choice energy program, which commenced electric service to customers on May 1, 2016. He also led the Power’s Regulatory and Legislative Affairs team responsible for representing the SFPUC and the City’s interests on state and federal energy regulatory and legislative issues.

Michael has also held positions at Columbia University’s Center for Energy, Marine Transportation and Public Policy and the Port Authority of New York and New Jersey where he worked on clean energy policy and developed clean energy programs and projects promoting electric vehicles, zero net energy buildings, microgrids, and renewable energy and energy efficiency.

Michael earned a BA in History, International Studies and Environmental Studies from the University of Oregon and holds a Master’s of Public Administration from Columbia University’s School of International and Public Affairs with a concentration in Energy Management and Policy.

Wendy Macy is the Chief People Officer overseeing comprehensive human resources services team responsible for a wide range of critical services including recruitment and retention of 2,300 employees across eight counties, people science and strategy, health and safety, employee and labor relations, equal employment opportunity, learning management, and payroll. Prior to joining the PUC, Wendy was General Manager Personnel for the City of Los Angeles, running a department of over 600 human resources professionals. She has over twenty years of executive experience in public agencies, serving as Personnel Director and Chief Operating Officer for the Los Angeles Unified School District, and Human Resources Director for the County of Sonoma. She earned her Bachelor of Arts from Harvard College and her law degree from Harvard Law School. Wendy also has a great deal of background, training and experience in mediation and conflict resolution.

Joel Prather is the Assistant General Manager of the Wastewater Enterprise. His professional background includes more than a decade at the SFPUC’s Wastewater Enterprise and over 20 years with the City and County of San Francisco. He started with San Francisco Public Works in the Bureau of Street and Sewer Repair and came to the San Francisco Public Utilities Commission in 2011 as a Maintenance Planner. Prior to being appointed to his current role, he held the position of Maintenance Manager, where he managed the day-to-day maintenance systems and practices for wastewater treatment facilities. He earned a BA in urban studies from San Francisco State University.

Steven Ritchie is Assistant General Manager of the Water Enterprise, where he oversees water system operations and planning from Hetch Hetchy through the Regional Water System to the City Distribution Division, and the management of lands and natural resources. He served as Manager of Planning from 1995-98. Previously, he managed the South Bay Salt Pond Restoration Project, a multi-agency effort to restore 15,100 acres of valuable habitat in South San Francisco Bay while providing for flood risk management and public access. He has served in management positions at the San Francisco Bay Regional Water Quality Control Board (1987-95), the CalFed Bay-Delta Program (1998-2000), and URS consultants (2000-04). He holds a B.S. and M.S. in civil engineering from Stanford University.

Stephen Robinson is the Assistant General Manager for Infrastructure, where he is responsible for capital programs and project implementation for SFPUC facilities, including the Water System Improvement Program, the Sewer System Improvement Program, and the Hetchy Capital Improvement Program. Previously, he was the Director of the Wastewater Enterprise Capital Program for SFPUC’s Infrastructure Division. He is a Professional Civil Engineer (CA) and a UK Chartered Civil Engineer with over two decades of planning, design, construction, and management experience in the water/wastewater sector. Prior to joining SFPUC he worked with MWH/Stantec as a consultant and served in the British Army as a Royal Engineer Captain. He has a master’s degree in Civil Engineering and Management from the Queens University of Belfast, Northern Ireland.