Diane C. De Felice

Diane C. De Felice



Skillfully navigates complex and controversial development and infrastructure projects. More than 25 years of experience helping clients accomplish their land use, environmental law and litigation goals. Significant experience in CEQA matters.

Diane offers her clients—developers, investors, cities and other private sector clients—land use and environmental law counsel, as well as proven litigation skills. With a deep understanding of public agency administrative processes, she streamlines complex environmental issues entwined with land use and planning matters so clients’ projects are able to break ground. Diane possesses industry-leading experience with the California Environmental Quality Act (CEQA), National Environmental Policy Act (NEPA) and Subdivision Map Act as well as the Coastal Act.

Large, complex and fast-moving matters with tight timelines are her passion. Clients seek out Diane for her strategic approach that balances development economics and legal issues to expedite projects and quell opposition. Whether consulting with public entities to help get a project built or defending one when challenged in court, she gets results. Her ongoing role as lead counsel for Cadiz Valley Conservation, Recovery and Storage Project, where she was responsible for obtaining and successfully defending six lawsuit challenges to the project’s entitlements, is a testament to her ability to deliver successful outcomes in long-ranging high profile infrastructure development work.

Diane’s commitment to excellence extends into the community. She provides pro bono land use counsel to Wolf Connection and also acts as a pro bono liaison for the firm’s California offices.

Representative Matters

Housing Development

  • Special counsel representing a nonprofit affordable housing organization regarding challenges to its more than 40-unit affordable housing complex in Santa Monica by a homeowners association (HOA). The complex is part of a larger redevelopment project that the HOA alleged violates CEQA, local land use plans and California Coastal Act. Successfully settled, avoiding litigation, by showing that construction of affordable housing units cannot be delayed without significant financial risk via a bond motion.

  • Land use and CEQA counsel for a national homebuilder obtaining entitlements for a 5,400-unit single-family residential and mixed-use project in Inland Empire including a General Plan Amendment, Specific Plan and Final Environmental Impact Report for development of a 1,500-acre property as well as obtaining approval of the Water Supply Assessment. Also defended subsequent litigation challenges including CEQA.

  • On behalf of a national homebuilder, obtained certification of the Final Environmental Impact Report and approval of the Development Agreement, General Plan Amendment and Specific Plan for development on 1,994 acres in Northern California, which included over 1,000 senior residential units, a 4-acre assisted living skilled nursing care facility, a 200-room hotel, neighborhood commercial uses, over 1,200 acres of habitat, 41 acres of on-site agricultural preserve and an additional off-site allocation.

  • Representing DignityMoves, a housing organization fighting to end unsheltered homelessness across California to deploy scalable, interim supportive housing on underutilized land with modular structures. Brownstein’s cross-disciplinary work includes transactional real estate and land use, corporate and tax advisory, and government relations. Brownstein has supported three sites, which are now fully approved and/or are operational, with a larger pipeline under negotiation.

High Stakes CEQA & Water Litigation

  • Successfully defended the entitlements for the Cadiz Valley Conservation, Recovery and Storage Project, a Southern California water supply infrastructure project designed to put 50,000 acre-feet per year to beneficial use over 50 years by conserving water lost to evaporation and delivering it to the Colorado River Aqueduct via a 43-mile pipeline. Led the successful defense of the project at both trial and in the California Court of Appeal, which upheld the environmental review against all challenges brought by opposing parties in six lawsuits. The appellate court also sustained the local management of groundwater and, in published opinions, endorsed the project’s structure as a template for processing P3s under CEQA.

  • Successfully represented Golden State Water Company (GSWC) in three phases of trial in the Los Angeles Superior Court. Phase 1 upheld GSWC’s (and other groundwater producers’)  longstanding interpretation of the Orange County Water District Act that recycled water produced within the geographical boundaries of the Santa Ana River watershed does not constitute a “supplemental source”. This ruling is highly significant for the 19 groundwater producers, including 13 cities, that rely on groundwater from the basin. Phase 2 of the trial addressed the ability of plaintiff Irvine Ranch Water Company to export water outside Orange County Water District boundaries. The court sided with plaintiffs that OCWD  noted it has a variety of administrative tools to prevent export, but it held that OCWD can only prevent “unlawful” export through the judicial process. The court’s Phase 2a ruling in Fall 2020 was in favor of GSWC and the producers group, denying IRWD’s causes of action, which sought to invalidate OCWD’s imposition of a production limitation and surcharge, a tool aimed at discouraging export outside OCWD’s service area.   

  • Successfully defended CEQA challenge to spring water agreement for Nestle Waters in trial and appellate courts. Provided NEPA, CEQA and land use compliance advice for project development including construction of bottling facility and construction of pipelines in federal forest land. 

  • Successfully defended CEQA challenge to 800,000-square-foot warehouse and distribution center for an international grocery store chain in Riverside County in state and appellate courts. Provided strategic land use and CEQA advice for a related expansion facility to enable distribution capacity to Northern California.


  • Successfully represented the City of Baldwin Park, a designated Disadvantaged Community under SB 535, on a land use and CEQA case related to a regional material waste facility and transfer station project sited within 300 feet of its border by the City of Irwindale. The court found CEQA deficiencies with the facility’s proposal to collect waste from commercial and non-commercial haulers all over the San Gabriel/Los Angeles region and required the City of Irwindale to vacate the project approvals. Challenge was based on unanalyzed environmental and land use impacts, which resulted in lack of analysis and/or insufficient mitigation exposing Baldwin Park’s 80,000 residents to traffic, odor, air and noise pollution. This victory halts development unless and until the project complies and responds to the court’s findings that the EIR was deficient.

  • Represented a water district before the California State Water Resources Control Board regarding renewal of water right permits for a USBR-owned reservoir and before the National Marine Fisheries Service with respect to Endangered Species Act compliance for listed steelhead. Representation included coordination with USBR, who holds the water right permits, and other project members holding water right entitlements in the reservoir for environmental compliance with CEQA, development of a biological assessment and opinion, and protection of downstream water rights interests.

  • Successfully defended the City of Long Beach’s efforts to green its facilities against claims of unlawful delegation of police power, violation of Brown Act open meetings law and various provisions of CEQA arising out of the Port of Long Beach’s implementation of the Port’s Clear Air and Clean Truck programs. Programs included diesel truck transition to lower emission equipment to improve air quality.

  • Represented a nationwide water resources company in a land swap for re-siting and rebuilding a reservoir, which involved multiple parties, as well as removing deed restrictions for parcels to optimize community infrastructure for water storage in Los Angeles.

Insights & Publications



  • J.D., 1990, Pepperdine University School of Law
  • B.A., 1984, University of California, Berkeley


  • California, 1990
  • U.S. Court of Appeals, Ninth Circuit
  • U.S. District Court, Central District of California
  • U.S. District Court, Northern District of California


Bizfed Los Angeles County Business Federation

Sustainable Development Council, Urban Land Institute, 2015-2019

Leadership Council, Urban Land Institute – Los Angeles

American Bar Association, 1991-present

California Business Properties Association

California Building Industry Association Legal Action Committee

Commercial Real Estate Women (CREW) Los Angeles

Legal Action Network for Development Strategies (LANDS)/National Association of Home Builders

Los Angeles County Bar Association, Litigation, Environmental Law and Real Estate Sections

State Bar of California, Litigation and Real Estate Sections

Attorney Coach, Mock Trial Program for Youths, Constitutional Rights Foundation, 1994-1999

Community Involvement


Board of Directors, Huntington’s Disease Society of America, Los Angeles Chapter

Pro Bono Liaison for Los Angeles office



Los Angeles Times, Inspirational Women Finalist, 2023

Los Angeles Business Journal, Women of Influence: Attorneys, 2023

Pasadena Magazine, Top Attorneys, 2023-2024

Southern California Super Lawyers, Environmental, 2015-2023

California Super Lawyers, 2016

Best Lawyers in America, 2023-2024