Jessica L. Diaz

Jessica L. Diaz



Environmental attorney with expertise in complex, niche water resources issues. Unique practice combining litigation and transactional work. Known for approachable manner. 

With an affable approach, Jessica Diaz embraces challenging legal questions and guides clients through uncertain terrain in the areas of water supply and land use in California. She also has experience with large, high-stakes real estate transactions related to water and assisting institutional corporate clients with niche water projects. 

Assisting clients on a broad range of water, environmental and land use matters, Jessica’s practice encompasses regulatory compliance, development entitlements, due diligence on real estate transactions, public law and litigation issues. She helps corporate clients, land owners and public agencies navigate issues related to common law water rights, the Sustainable Groundwater Management Act, water diversion regulations, the California Environmental Quality Act, California Coastal Act, State Water Resources Control Board proceedings, mutual water companies, land use law, easements, takings challenges, well sharing agreements and disputes, government organization issues, and emerging legal questions faced by developers, water providers and water users.

Prior to her legal career, Jessica worked in both state and local government, informing her ability to advocate for the needs of public agency clients as well as private entities in the public agency sphere. She worked as an aide for a California state legislator, served as the district director for a Sonoma County supervisor and led a community-based nonprofit focused on affordable housing, labor and environmental issues.

Representative Matters

Recent Experience

  • Special water counsel for private equity firm One Rock Capital in connection with the completion of due diligence in support of the agreements to acquire Nestle Waters North America, the world’s largest bottled water company for over $4 billion. Brownstein water counsel led due diligence efforts on water assets, water rights, water supplies and offered industry and supply risk assessments for Nestlé Waters North America’s U.S. business, including regional spring water brands, production facilities and infrastructure related to the water business.

  • Counsel to a broad group of agricultural stakeholders in the Salinas Valley providing assistance with the development of a Groundwater Sustainability Agency that includes significant participation by the agricultural groundwater users within the valley.

Insights & Publications



  • J.D., 2014, University of California, Berkeley, School of Law, Order of the Coif
  • B.A., 2006, Harvard University


  • California
  • Alaska

Community Involvement


ACWA Board of Directors, Chair of Legal Affairs Committee.

Member, Updating Water Rights Data for California (UPWARD) Advisory Member, Updating Water Rights Data for California (UPWARD) Advisory

Law Firm Antiracism Alliance, Housing/Home Ownership Working Group

Santa Barbara Zoo, Board of Directors

H2O Women Conference, Co-Chair

Water Education Foundation, 2018 Water Leader Class

Santa Barbara Mock Trial Competition, Judge

McBaine Honors Moot Court Competition, Brief Judge



Best Lawyers: Ones to Watch in America, 2024

2020 Pacific Coast Business Times 40 Under 40

2018 Santa Barbara County Bar Association Pro Bono Award

2018 Young Water Professional, Water & Wastes Digest

Water Leaders Class of 2018, Water Education Foundation

2014 Land Use Law Writing Award, Berkely School of Law

Best Petitioner Brief, 2014 McBaine Moot Court Competition