Gregory J. Patterson

Partner, Ventura County Office


Greg Patterson is a partner in Musick Peeler’s Ventura County office and is a member of the Public and Environmental and Litigation practice groups.  Mr. Patterson has nearly three decades of experience primarily in the area of environmental law, representing both private and public sector clients.  His range of experience includes a mixture of environmental litigation at the federal and state level, environmental audit and regulatory compliance counseling, and representation of parties before federal and state administrative agencies.

As an adjunct to his environmental practice, Mr. Patterson also has become very knowledgeable regarding the application of the procedural and substantive requirements of Proposition 13, 26, and 218, especially as applied to groundwater extraction fees and related environmental fees.

At the federal level, Mr. Patterson has extensive experience representing clients under the Comprehensive Environmental Response Compensation and Liability Act, the Resource Conservation and Recovery Act, the Clean Water Act, the Clean Air Act, the National Environmental Protection Act, and the Endangered Species Act. 

At the state and local level, Mr. Patterson represents clients involving California’s Hazardous Substances Control Act, the Porter Cologne Water Quality Control Act, California’s Clean Air Act, Fish and Game Code Act, California Environmental Quality Act, and Proposition 65.  He has represented parties in numerous matters before the State Water Board, the Regional Water Quality Control Boards, the Department of Toxic Substances Control, the Department of Health Services, and the Air Quality Control Districts on various administrative, civil and criminal enforcement actions.

Mr. Patterson is experienced in handling complex environmental issues encompassing:

  • Environmental litigation cost recovery actions at the stated and federal level
  • Negotiation and drafting of consent orders, corrective action agreements, and administrative compliance orders
  • Representation of companies and persons charges with environmental criminal violations and civil violations including actions brought under the Business and Professions Code
  • Representation throughout the remediation of contaminated properties, including oversight of Phase 1 and Phase 2 investigations, compliance with NCP requirements, negotiating economically feasible remediation plans, and closure requirements
  • Counseling with respect to federal and state laws governing hazardous waste management and disposal, solid waste management, medical wastes, air emission requirements, water discharge and pollution requirements, storm water management, contamination and spill reporting obligations, underground storage tank requirements, groundwater and water resource management, and occupational health and safety requirements
  • Environmental risk avoidance and risk allocations, including due diligence reviews and use of environmental insurance products
  • Indoor air quality matters, including vapor intrusion, asbestos management, and compliance with asbestos abatement regulations
  • Defense of claims of violations of Proposition 65 warning requirements
  • Review of environmental impact statements and related land use documents
  • Compliance with Propositions 13, 26 and 218 procedural and substantive requirements
  • defense of environmental criminal violations

Representative Matters

City and Public Agency Representation

  • Representation of the City of Santa Monica in several actions against multiple oil companies involving the contamination of the City’s ground water supplies with MtBE.This was one of the first cases in the country arising from MtBE contamination of a drinking water supply
  • Representation of the Los Angeles Unified School District in multiple matters to recover costs associated with the contamination of school property.These efforts resulted in the recovery of in excess of twenty million dollars
  • Representation of the City of American Canyon is an action against a large bottling company to enforce waste discharge requirements under the City’s NPDES permit.The bottling company paid over seven million dollars in fines and settlement, the largest such fine for this type of municipal discharge violation
  • Representation of the City of Pasadena in an action involving contamination of a number of the City’s drinking water wells
  • Representation of a water conservation district in four separate actions challenging the validity of the district’s ground water extraction charges under Propositions 13, 26 and 218.Representation included two bench trials to conclusion.Mr. Patterson also appeared before the Court of Appeal, Second Appellate District and argued on the district’s behalf regarding the correct interpretation and application of Propositions 13, 26 and 218 to the district’s ground water extraction charges

Private Party Representation

  • Representation of various companies in multi-party CERCLA and RCRA actions. Representation has included private party cost recovery actions as well as multi-party USEPA Superfund actions
  • Representation of numerous companies defending against citizen suits alleging violations of Proposition 65 warning requirements
  • Representation of companies defending against alleged storm water violations
  • Representation of a private water company in multiple lawsuits involving the San Gabriel Valley ground water Superfund sites
  • Representation of a large national manufacturing company in a unique case involving the application of CEQA in the company’s successful efforts to gain approval of its product for use in commercial and residential developments
  • Representation of manufacturing companies in efforts to obtain variances from the Air Quality Management District
  • Representation of multiple clients involved in property site cleanups, including interaction with the oversight agencies, purchase and sale of the properties, risk allocation and use of insurance products
  • Representation of multiple companies and individuals charged with civil and criminal violations of environmental laws


While attending Southwestern University School of Law, Greg was a member of the SCALE program, an accelerated two-year program.  He also graduated first in his class.


  • State Bar of California, Environmental Section
  • Los Angeles County Bar Association, Environmental Section
  • Ventura County Association of Water Agencies