O’Melveny’s Water Practice helps a wide range of clients navigate all of the complicated legal issues implicated by this ever-more-important resource.

From complex deal work to high-stakes litigation, our water-related experience extends to almost every conceivable issue a water business, water investor or financier, major water user, or government entity could face.


O’Melveny has been at the forefront of water litigation in California for over a century, including the first groundwater basin adjudication ever filed in the state. In the decades since, we have accumulated an unrivalled record of accomplishment counseling clients in some of the most complex water cases throughout the United States. We have successfully represented clients in litigation related to the development of tidelands and coastal areas, disputes involving the demarcation of water agency boundaries and allocation rights, water issues related to oil and gas exploration and production, and high-profile controversies involving agricultural water allotments and access. Our group includes well-known thought leaders in the area, as well as public servants, including a Special Master for the United States Supreme Court in state v. state water litigation, and General Counsel of the New York Department of Environmental Protection. Our water team is at the forefront litigating the most complicated questions arising out of California’s landmark Sustainable Groundwater Management Act (SGMA), as well the contours of federal reserved water rights. Our water trial lawyers were named the best Environmental/Natural Resources litigators in California in 2019, and The American Lawyer has recognized our water litigators’ signature victories in groundwater litigation in its national Litigators of the Week reports. Our team regularly speaks at the country’s largest water conferences, and one member of our group has trained judges on water law questions for years. There is no piece of water litigation that our team cannot handle—matching deep substantive knowledge and experience in water law with best-in-the-country litigation skills.


We offer a multidisciplinary team of attorneys experienced in various corporate and regulatory matters related to the water and wastewater industries. Working seamlessly with our environmental law experts, land use, and regulatory lawyers, we assist our clients both on the feasibility of proposed projects, and in the documentation of the transaction to protect our clients' rights and limit their liability.

The practice regularly handles matters involving:

    • Water Rights/supply
    • Water Rights/infrastructure for long term development projects
    • Acquisition of private water companies/systems
    • Water facilities for master planned communities
    • Water project financing
    • Water transfer and wheeling agreements
    • Produced water facilities
    • Environmental
    • Water quality/contamination issues
    • Development of water infrastructure facilities 
    • Pipeline systems
    • Tidelands and related issues

Water Law Thought Leadership

  • Legal Control of Water Resources - Buzz Thompson is the lead author of the principal book on water law in the United States (now in its sixth edition)
  • Wall Street Journal - Buzz Thompson was quoted in a December 2019 Wall Street Journal article on water disputes in Florida and the southeastern United States
  • 2019 Groundwater Law Legislation Forum - Russ McGlothlin was a panelist on the “SGMA Status and Forecast” panel at the 2019 Groundwater Law and Legislation Forum
  • 2019 ABA Conference - Heather Welles was a panelist at the American Bar Association’s 37th Annual Water Law Conference
  • 2018 City Attorneys’ Annual Conference - Russ McGlothlin delivered a speech called “How SGMA Will Affect Municipal Groundwater Suppliers” at the 2018 City Attorneys’ Annual Conference
  • Los Angeles Times - Matt Kline, Buzz Thompson, and Heather Welles authored a June 2018 op-ed in The Los Angeles Times emphasizing the water-related problems that could result from 2018’s “Three Californias” ballot initiative
  • 2018 ABA Conferences - Buzz Thompson was a panelist at the American Bar Association’s 36th Annual Water Law Conference and at its 47th Annual Spring Environment, Energy, and Resources Conference
  • National Public Radio (NPR) - Matt Kline was interviewed by NPR’s “Marketplace” on the increasing use of public-private partnerships for the construction and redevelopment of drinking and waste water infrastructure
  • KQED - Heather Welles was interviewed by San Francisco PBS broadcaster KQED about recent proposals from the California Water Resources Control Board to restrict water usage
  • Litigation
    • Served as Special Master in Montana v. Wyoming (137 Original) water rights dispute.
    • Major energy company in water rights and Proposition 65 matters in California.
    • Serve as counsel in connection with the Sustainable Groundwater Management Act (SGMA).
    • Aramark in numerous property contamination cases (including Superfund cases) across the country.
    • Exxon Corporation in an array of civil, criminal and administrative proceedings over the past 20 years relating to the Exxon Valdez oil spill.
    • Lennar Corporation in dismissal of several environmental matters relating to its redevelopment of former military bases in the Bay Area, including the Hunters Point Shipyard.
    • Parsons Engineering in multiple lawsuits related to its wastewater treatment facility operations.
    • Tosco Corporation in settlement of citizen suit brought under RCRA and the Clean Water Act by Northern California River Watch relating to the release of hydrocarbons at a petroleum distribution facility in Humboldt, California.
    • Major utility in water contract dispute with Central Valley irrigation districts and environmental group.
    • Manufacturer in metals and volatiles contamination of groundwater and major cleanup site in San Francisco.
    • Central coast vineyard developer in a citizen’s suit relating to alleged violations of Fish & Game regulations arising from development of groundwater wells and deep ripping through alleged vernal pools.
    • Pesticide manufacturer in the defense of groundwater contamination claims by Central Valley municipalities.
    • Major railroad in numerous property contamination cases (including Superfund cases) throughout California.
    • Major financial institution in litigation over trust real estate contaminated with dry cleaning solvents.
  • Project Finance
    • Anderson Regional Joint Water System (South Carolina) in $58.6 million in financing bonds.
    • Leading financial institution in underwriting a US$11 billion bond issuance by the California Department of Water Resources.
    • Underwriters in the issuance of over $1.9 billion in bonds for the Los Angeles Department of Water and Power.
    • New York Municipal Water in its US$117 million financing of water and wastewater facilities.
    • San Jose – Santa Clara Clean Water Financing Authority in $106 million financing bond.
    • Underwriters in the US$375 million financing of improvements to the City of San Diego’s municipal wastewater systems.
    • The Metropolitan Water District of Southern California (the District) handling finance and interest rate swap arrangements, as well as general District state law matters.
    • Seven Dutch water boards in connection with eight cross-border leases of water treatment facilities. The water boards are the governmental entities that are responsible for water management systems in the Netherlands, a critical function in that country.
    • Consortium consisting of Degremont S.A. and Suez Lyonnaise des Eaux in connection with the financing of a wastewater treatment plant for the District of Bogotá, Colombia by means of a US private placement of senior debt for which the Inter-American Development Bank provided a partial risk guarantee. The Salitre Project was the first capital markets financing of an emerging markets water project and the first to employ an IADB partial risk guarantee.
  • Privatization
    • American States Utility Services in its US$430 million privatization of military base water and wastewater systems.
    • Southern California Water Company on various matters related to the privatization of municipal water systems throughout California.
    • US Filter in its privatization of municipal water systems in the US and internationally.
    • Various local governments on privatization of water and sewage systems in the Dominican Republic, Bolivia, Argentina, Peru and Mexico.
  • Water Purchase/Sale Agreements and Operations and Maintenance Transactions
    • Metropolitan Water District of Southern California on various transactions, including water exchange and transfer, storage, bond financing and facility construction.
    • Several multimillion dollar design, build, operations and maintenance transactions regarding wastewater treatment and sale of reclaimed water in Western U.S.
  • Investments and Acquisitions
    • AECOM in its acquisition of water/wastewater specialist Boyle Engineering.
    • GIC in its £3 billion acquisition of Kelda Group plc.
  • Real Estate Development, Environmental, Permitting, Land Use and Regulatory
    • Several significant agriculture industry companies on acquisition of farming property and California water rights.
    • Commencement Bay NPL Site (Tacoma, WA). O’Melveny provided group representation and completed an allocation for 80 parties in connection with a $40 million sediment removal/capping project for Thea Foss Waterway. We coordinated a de minimis settlement and recalcitrant enforcement efforts with EPA Region.
    • Eton Park, Goldman Sachs and Och-Ziff in matters relating to the 2007 Cosco Busan oil spill in the San Francisco Bay.
    • O’Melveny represented 150 private third-party defendants in the US$35 million settlement of claims by the State of New Jersey against manufacturers of DDT and Agent Orange products, which are alleged to have contaminated the Passaic River and Newark Bay area. the settlement resolves the State’s claims for over US$500 million in past and future clean-up costs, as well as natural resource damage assessment expenses, economic, and other damages.
    • Major private equity investor in the analysis of the water rights of multiple real property parcels overlaying several aquifers.
    • Port of Los Angeles in several matters related to development of coastal and tidelands areas, including land use permitting and project approvals by local jurisdictions and State Lands Commission. Port of Oakland in several matters related to the permitting, environmental review and water quality issues associated with the operation of and redevelopment of Port facilities.
    • Waste management and manufacturing companies in several regional groundwater contamination matters, including several that resulted in large capacity treatment systems from which treated water was distributed as drinking water. These matters required extended negotiations and permitting with numerous water purveyors and Watermasters, as well as federal, state and local jurisdictions.
    • Waste management and manufacturing companies in surface water and sediment contamination cases throughout the United States.
    • Southern California Water Company as the owner of public water utility property being condemned.