O’Melveny Worldwide


In an age of prolonged drought and climate challenges, O’Melveny’s Water Group helps manage every legal, business, and regulatory aspect of this crucial resource.

People Places Planet Podcast: How Can Business Help Solve the Freshwater Crisis?

In an age of prolonged drought and climate challenges, O’Melveny’s Water Group helps manage every legal, business, and regulatory aspect of this crucial resource.

People Places Planet Podcast: How Can Business Help Solve the Freshwater Crisis?

Our Water Group counsels clients on the full spectrum of legal services facing water investors and financiers, agricultural companies, major water users, and government agencies, including high-stakes transactions, complex litigation, and regulatory issues. With water scarcity increasingly a matter of economic, political, environmental, and humanitarian concern, O’Melveny counsels clients on:

Disputes & Litigation

As the oldest law firm in Southern California, and one of the largest in the state, O’Melveny has been at the forefront of water litigation in the West for more than a century. Through the decades, we have accumulated an unrivaled record counseling clients in some of the nation’s most complex water cases. We have successfully represented clients in litigation concerning the development of tidelands and coastal areas, disputes involving the demarcation of water agency boundaries and allocation rights, litigation over federal reserved water rights, water issues related to oil and gas exploration and production, and high-profile controversies over agricultural water allotments and access.

This experience includes mediating the most challenging questions arising out of California’s landmark Sustainable Groundwater Management Act (SGMA), where we served as lead counsel for the first contested post-SGMA groundwater basin adjudication filed in California, Las Posas Water Rights Coalition v. Fox Canyon Groundwater Management Agency. Our many years of dedication to the water sector leads to more efficient processes, more productive dialogue, and more equitable solutions for all parties involved. Our ultimate goal is to fashion win-win outcomes in complicated disputes, driving sustainable, equitable use of resources.

When settlement is not an option, our nationally recognized team comes to trial ready to win. We lead trial victories, bring to bear years of experience working collaboratively with water-sector experts, and help argue and shape law and policy. O’Melveny’s appellate team is among the finest in the country, and water disputes need strong appellate counsel at the ready. Our years of experience with water litigation, deep bench, and core commitment to water law and policy leadership distinguish O’Melveny’s Water Group from any other in the country.

Water Quality and Environmental Compliance

Drawing on our team’s experience in academia and government, we help clients with significant water operations satisfy their state and federal water regulatory obligations, including the treatment of water used in manufacturing and commercial operations, wastewater, and other commercial uses. Our environmental attorneys have substantial counseling and litigation experience with compliance inquiries and enforcement actions brought by the US Environmental Protection Agency (EPA), state environmental agencies, state attorneys general, and third parties. We are particularly fluent in many of the most complicated environmental rules governing the country’s water supply, including the Clean Water Act (CWA), the Safe Drinking Water Act, and California’s Proposition 65.

Members of our team have been highly active in the development of SGMA, as well as laws designed to reform judicial procedures related to groundwater basin disputes. We have an exceptional understanding of high-stakes groundwater management issues in California.

Water Infrastructure and Agreements

Our water infrastructure attorneys help bring a diminishing resource to a growing population. We guide project developers, investors, sponsors, governmental entities, and others within the water sector in the development and operation of water-related infrastructure and investment projects, including groundwater banking, seaports, wastewater treatment facilities, chilled water facilities, pipeline systems, agricultural properties, and other water-related infrastructure assets. We also advise clients on all facets of water purchase and transfer agreements, including private arbitrations, sales to municipalities, stakeholder negotiations, and the establishment of rules for marketing groundwater.

Water Project Financing

Our corporate attorneys help secure the financing of water projects, facilities, and systems, both domestically and internationally, advising clients that include underwriters, lenders, sponsors, and others. Our full-service team also counsels clients on financing of and investment in new water-related technologies and security, including advice on tax implications and issues involving water-related projects and investments.

Thought Leadership in the Water Sector

O’Melveny water attorneys are thought leaders on the legal issues related to global water challenges. Barton H. “Buzz” Thompson, Jr. is an of counsel in O’Melveny’s Water Group. Buzz is the Robert E. Paradise Professor of Natural Resources Law at Stanford Law School, a professor in the Stanford Doerr School of Sustainability, and a Senior Fellow of the Stanford Woods Institute for the Environment. He also leads Stanford’s Water in the West program. The author of multiple books on water law and policy, he is one of the world’s leading experts on water issues, with more than forty years of experience. Buzz and our Water Group practice leader Matt Kline co-teach the “Business of Water” at Stanford University, bringing experts from across the industry together with graduate students in a range of disciplines. All of our water attorneys, including Russ McGlothlin, Heather Welles, and Zach Smith, regularly speak at prominent conferences and seminars on water-related issues around the country, and have authored numerous articles in industry publications concerning current and complex water issues facing the water sector.

Apollo Global Management

Represented Apollo in its US$250 million capital investment into the Cadiz Valley Water Conservation, Recovery and Storage Project in California’s Mojave Desert, including providing advice on contractual, regulatory, and permitting matters.

California Resources Corporation

Represented California Resources Corporation (CRC) in a bench trial over constitutional issues related to Monterey County Measure Z, which would have prohibited wastewater and energy companies from operating their businesses in a manner previously authorized by the State of California. O’Melveny successfully showed that Measure Z violated CRC’s due process rights and was an unconstitutional taking of property. 

Coachella Valley Water District

O’Melveny defended the Coachella Valley Water District and its board in a case brought over water rights in one the nation’s agricultural and tourism heartlands. O’Melveny secured summary judgment showing that CVWD has been an excellent steward of resources in the valley and has not harmed any party. This victory earned O’Melveny national “Litigator of the Week” recognition.

Home Depot

Defended and settled civil and administrative proceedings by environmental agencies and state attorneys general related to water and hazardous waste handling practices.

Las Posas Farming Group

In a first-of-its-kind comprehensive groundwater adjudication under California’s Sustainable Groundwater Management Act (SGMA), adopted in 2015, O’Melveny’s Water Group represented a diverse group of landowners and farmers in a multi-stage adjudication involving Las Posas Basin in Ventura County. O’Melveny successfully led negotiations to reach settlements in three phases of trial and the development of a stipulated judgment, which was adopted by the Santa Barbara Superior Court. The court’s ruling was O’Melveny’s third and capstone trial win in this ground-breaking legal setting—California’s first contested adjudication of groundwater rights filed in the wake of SGMA.


Representing Lennar, a Fortune 500 construction and real estate company, and a number of its subsidiaries in connection with environmental litigation matters related to its redevelopment of the Hunters Point Shipyard in San Francisco, California.

Ontario Teachers’ Pension Plan

O’Melveny coordinated the pension plan’s acquisition of Washington State’s Broetje Orchards, one of the largest, vertically integrated apple companies in the United States, including related water rights agreements and environmental compliance issues. This is just one of many agriculture-focused acquisitions in which O’Melveny has served as lead deal counsel or has done deep-dive water-rights due diligence.

OPV Coalition and 50 landowners and growers in Ventura County

O’Melveny has filed a groundwater adjudication in California, involving adjudicating all the rights to groundwater in the Oxnard and Pleasant Valley groundwater basins located in Ventura County. The O’Melveny Water Group is representing the OPV Coalition and its members, comprising more than 50 large landowners and growers in Ventura County. This ambitious adjudication is one of the largest of its kind, as the two groundwater basins contain the major population centers of Oxnard and Camarillo as well as a U.S. Navy base. 

Port of Oakland

O’Melveny counseled the Port of Oakland in several matters related to financing, permitting, environmental, and water-quality issues stemming from the operation of and redevelopment of Port facilities. This is one of scores of infrastructure projects that O’Melveny has handled, which also include airport, rail, and water conveyance projects.

Rancho California Water District

Advised local independent water district in Riverside County on water rights issues in the Temecula-Murrieta Groundwater Basin.

T2 Borrego

O’Melveny represented T2 Borrego LLC, the owner of a high-end golf course and large recreational development project in San Diego County, California, in the adjudication of the Borrego Springs Groundwater Basin. Our Water Group played a central role in negotiating and prosecuting the court’s adoption of a stipulated judgment pursuant to California’s groundwater adjudication statute. The judgment serves as an approved alternative to a groundwater sustainability plan required by California’s Sustainable Groundwater Management Act (SGMA). O’Melveny continues to represent T2 Borrego in all post-judgment proceedings before the court and the watermaster in relation to the judgment’s implementation.

Representative Clients
Apollo Global Management
California Resources Corp.
Coachella Valley Water District
Golden State Water Company
Home Depot
Las Posas Farming Group
Los Lomas Mutual Water Company
Pomona Farming
Rancho California Water District
Sunshine Agriculture
T2 Borrego
Wonderful Citrus

Top tier nationally for Environmental Law

—US News & World Report/Best Lawyers’ “Best Law Firms” survey (2023)

Legal Impact Case of the Year

Benchmark Litigation (2020)

Twice named “California Environmental/Natural Resources Litigation Firm of the Year”

Benchmark Litigation (2019-20)

“A strong team possessing vast experience in documentation advice as well as health and safety counsel on significant transactions, financings and restructurings…. Relied upon by private equity firms to ensure all environmental risk and compliance requirements are properly assessed.”

Chambers USA

For three consecutive years, Matt Kline named “Environmental/Natural Resources Attorney of the Year” 

—Benchmark Litigation (2019-21)

Russ McGlothlin recognized as “Lawyer of the Year” for Water Law in Los Angeles, CA

—Best Lawyers (2023) 

Heather Welles named a “Rising Star” in Environmental Law

—Law360 (2023)