Sean chairs the firm’s largest practice group, business litigation. Sean is a litigator and water lawyer with nearly 20 years of experience advising Fortune 500 companies and other businesses on a broad range of disputes involving water rights, environmental permitting, partnership and shareholder interests, and real estate.

Sean has a strong track record of success in the courtroom (see Representative Cases, below) and in achieving advantageous settlements for his clients. He has wide-ranging trial experience in complex water rights litigation in state and federal court, and has been lead counsel in each trial to resolve contested water right claims in the Gila River General Stream Adjudication.

Sean helps his clients acquire and protect their surface water and groundwater supplies used for mining, industrial, municipal, and agricultural purposes. Sean advises clients on a wide range of Western water rights issues, including the Drought Contingency Plan (DCP) and other Colorado River issues. Sean has in-depth experience litigating federal reserved water right claims and issues concerning subflow.He also litigates issues arising under the National Environmental Policy Act (NEPA) and the Endangered Species Act (ESA), and has successfully defended land ownership interests in navigability for title proceedings under the Equal Footing Doctrine.

Sean handles cases throughout the West. He practices regularly at the trial and appellate levels in state and federal courts, as well as before a variety of administrative boards and commissions. Sean is an author on various natural resources topics, including implementation of California’s Sustainable Groundwater Management Act (SGMA).

When not in a court room, Sean is spending time with his wife and three children, rooting for the Notre Dame Fighting Irish, or playing guitar with his band, Retro-Active.


  • J.D., with honors, Notre Dame Law School
  • B.S., Santa Clara University

Areas Of Practice

Our experienced agricultural attorneys provide a broad range of assistance to clients, both domestically and internationally, in many areas of agribusiness and agricultural law.

Experienced, forward-thinking advocates who go beyond the expected for clients in dispute prevention and resolution.

We have over 130 years of experience representing clients in minerals development.  

We are the forward-thinking natural resources, energy and environmental law team that innovates to ensure industry and businesses successfully navigate the ever-changing regulatory climate.


  • Water Law

Representative Cases

  • Recently represented a real estate developer blocked from selling lots due to the sanitary district’s wrongful refusal to approve service.  Conducted an expedited evidentiary hearing and demonstrated for the Court that the district’s action constituted an illegal moratorium.  Complete relief was obtained for the client within weeks of filing the complaint. See the order here. Sean then prevailed in the Court of Appeals, and secured separate attorneys’ fees awards in both courts. See full Court of Appeals decision here.
  • Acted as lead counsel in the first trial to resolve a set of contested water right claims in the 44 year history of the Gila River General Stream Adjudication.  Defeated a host of federal reserved right claims, including the Federal Government’s claim to all of the water that flows naturally within the wilderness area.  In re Aravaipa Canyon Wilderness Area, No. W1-11-3342, Superior Court of Arizona, Maricopa County. See full ruling here.
  • Acted as lead counsel in each of the successive trials to resolve water right claims in the Gila River General Stream Adjudication.
  • Defeated the adverse party’s federal reserved right claims to the flow of two streams through the exclusion of expert testimony concerning streamflow quantification. Prior to trial, obtained summary judgment on claims to an additional 34 individual water sources. In re Redfield Canyon Wilderness Area, No. W1-11-2664, Superior Court of Arizona, Maricopa County.
  • Secured judicial determinations in another case concerning (1) the federal reserved right claimant’s obligation to account for available surface water supplies before obtaining a right to groundwater and (2) the limitations on the water sources available to, and places of use for, federal reserved rights. In re Fort Huachuca, No. W1-11-605, Superior Court of Arizona, Maricopa County.
  • Represents a client in litigation concerning the Bureau of Land Management’s federal reserved right claims for the San Pedro Riparian National Conservation Area. In re San Pedro Riparian National Conservation Area, No. W1-11-232, Superior Court of Arizona, Maricopa County.
  • Successfully defended a large private landowner against the State of Arizona’s claims of ownership of lands pursuant to the Equal Footing Doctrine. The dispute involved five separate proceedings requiring the development of extensive historic evidence and technical reports, the presentation of expert witness testimony, the cross-examination of various adverse expert witnesses during several weeks of hearings. Based on these proceedings, it was determined that the State of Arizona does not own the lands at issue. In Re: Determination of Navigability of the San Pedro River, the Santa Cruz River, the Gila River, the Verde River, and the Salt River, Before the Arizona Navigable Stream Adjudication Commission.
  • Represented an industrial client in successfully opposing a legal challenge to the Aquifer Protection Permit issued to the client by the Arizona Department of Environmental Quality. The case involved complex competing expert testimony concerning hydrologic issues and groundwater modeling. In re Aquifer Protection Permit No. : P-106100, Nos. 12-002-WQAB, 12-003-WQAB, and 12-004-WQAB (Consolidated), In the Office of Administrative Hearings.
  • Represented a national business in connection with an antitrust investigation concerning a merger involving the client’s two largest competitors. The representation involved the development of evidence of relative market share and coordination with federal regulators to expose the ramifications of common ownership of the two competitors. The result of the investigation was a successful settlement requiring divestiture of one of the competing businesses.

Awards and Honors

  • Best Lawyers in America®, Commercial Litigation, Litigation – Environmental, Water Law, 2019-2022
  • Southwest Super Lawyers®, Business Litigation, 2021
  • Chambers USA, Leading Lawyers for Business, 2019-2021
  • Benchmark Litigation, Future Star, 2019
  • Benchmark Litigation, Top Litigator Under 40, Future Star, 2017-2018
  • Benchmark Litigation, 40 & Under Hot List, 2016, 2018
  • Southwest Rising Stars®, Business Litigation, 2012-2018
  • Benchmark, Rising Stars, 2016
  • AV® Preeminent™ Peer Review Rated (the highest rating available), by Martindale-Hubbell

Articles and Presentations

Professional and community activities

  • Guitarist, Retro-Active, performing to benefit Alice Cooper’s Solid Rock Teen Center. See clip here.
  • Guitarist, IC/DC, performing to benefit Sentinels of Freedom (a nonprofit assisting wounded veterans complete their higher education). See clip here.
  • Notre Dame Club of Phoenix, Member
  • Trial Practice Section, State Bar of Arizona, Member
  • Environmental and Natural Resources Section, State Bar of Arizona, Member
  • Colorado Bar Association, Member
  • Environment and Natural Resources Section, State Bar of Nevada, Member
  • Maricopa County Bar Association, Member
  • Notre Dame Club of Phoenix Board of Directors, past Member
  • St. Matthew’s Interactive Learning Experience, past Chair
  • Mining and Mineral Extraction Committee, American Bar Association, past Vice Chair-Membership


  • Arizona
  • California (pro hac vice pending)
  • Colorado
  • Nevada
  • U.S. District Court, District of Arizona
  • U.S. District Court, District of Nevada
  • U.S. Court of Appeals, Ninth Circuit