Janathan L. Allen, APC is a law firm based in Southern California. Our attorneys advise individuals and businesses in the United States and abroad regarding a variety of important matters related to tax, business, estates and more.

Janathan L. Allen

Janathan Allen International Domestic Tax Attorney

A Montana native, Ms. Allen brings international tax, accounting, finance knowledge to Allen Barron, Inc. and law expertise to Janathan L Allen, APC. Allen has worked with a diverse group of businesses, advising clients in legal, financial and tax arenas.

Beginning her career in the public accounting arena, she moved into the private sector as tax director for a biotech firm, Hybritech, Inc. She progressed to controller and CFO/Legal Counsel positions for a number of San Diego companies before becoming a partner in Allen Barron, Inc. and founding Janathan L Allen, APC.

She has led seminars throughout California on Tax-Advantaged Corporate Structures and Tax Minimization, and appeared as a panelist for Tech Coast Venture Network in a roundtable discussion for venture capital and angel financing.

Areas of Practice

  • International and Domestic Tax Law
  • Business & Commercial Law
  • Business Formation and Entity Selection
  • Estate Planning
  • Trusts


Southwestern University School of Law, Los Angeles, California

  • J.D.

University of San Diego School of Law, San Diego, California

  • LL.M.
  • Major: Taxation

University of San Diego

  • M.B.A.
  • Major: International Finance

University of Montana

  • B.S.
  • Major: Accounting

Timothy J. Grant, Of Counsel

Tim Grant has held the highest possible AV Preeminent® rating from Martindale’s nationwide attorney peer review rating since 1993. San Diego Magazine and both have recognized him as a “Top Lawyer” in the field of Business Law from 2011 through 2017, and he has been listed as a “Recommended Insurance Attorney” by Best’s Review since 2003.

Tim earned his Bachelor of Arts degree in 1979 from San Jose State University where he also participated in intercollegiate sports and spent a semester as an intern in the California State Senate. After working a few years in California’s high-tech Silicon Valley area as an outside sales representative, he pursued his law degree at the Santa Clara University School of Law, which included a semester abroad at Oxford University, England. He earned his Juris Doctor degree from Santa Clara University in 1985.

The majority of Tim’s law practice is devoted to the defense of businesses and individuals along with construction claims, but he also has successfully prosecuted business litigation, collection, personal injury, products liability, and medical malpractice claims. In the course of his legal career he has successfully represented countless insured and self-insured clients up through trial and appeal on personal injury, property damage, breach of contract, unfair business practices and business torts, products liability, major trucking and auto accidents, construction defect, and professional liability claims.

On the business side of the practice, being able to mentor young attorneys is the role he finds most rewarding.  Throughout his schooling and during his 30+ years of legal practice, he has carried with him the philosophy that while a certain amount of skill and success is natural, most only comes through hard work and dedication.

Areas of Practice

  • Business Litigation
  • Construction Law / Construction Defect
  • Products Liability
  • Personal Injury / Property Damage
  • Major Trucking & Auto Claims
  • Professional Liability
  • General Liability – Insurance Defense


University of Santa Clara

  • J.D.

Magdalen College, Oxford University, England

San Jose State University

  • B.A.

Admitted – State Bar of California

Professional Associations

  • California Bar Association & American Bar Association
  • Claims & Litigation Management Alliance (CLM)
  • Defense Research Institute (DRI)
  • San Diego County Bar Association & San Francisco County Bar Association
  • Trucking Insurance Defense Association (TIDA)
  • California Trucking Association (CTA)
  • Lecturer on loss control & trial practice issues


William K. Koska, Of Counsel

For over four decades, Bill has repeatedly produced favorable results in contentious trial work and litigation. He has prosecuted landmark condemnation litigation against state agencies for their failure to properly supervise and implement an effective cleanup plan at a CERCLA site, and prosecuted the contaminator of the site without becoming involved in the then-pending CERCLA litigation. Other real estate issues he handles include eminent domain, inverse condemnation, flooding, landslides, earth movement, environmental issues, boundary disputes, partition issues, lateral/subjacent support issues, and construction defect. He also has defended products liability cases on issues ranging from brain injuries and serious burn injuries to inhalation of asbestos, mold and other cancer-causing chemicals, loss of body parts and death, as well as injury claims based on helmet issues. Finally, he has defended and prosecuted civil cases on behalf of horse owners and trainers, including allegations of improper drug administration, personal injury to riders, breach of contract, and livestock injury claims.

Bill has held the highest possible AV Preeminent® rating by Martindale’s nationwide attorney peer review rating since 1976. He also was listed by San Diego Magazine in 2013–2017 as a “Top Lawyer” in the fields of Environmental/Real Estate Law.

When he is not involved with his busy practice, Bill spends time with his wife and two young daughters on their small horse property in Poway, where he exercises and trains his own horses.

Areas of Practice

  • Environmental Law
  • Product Liability
  • Real Estate
  • Asbestos
  • Equine Litigation
  • Water Litigation / Rights


University of Arizona, College of Law

  • J.D.

University of Florida

  • B.S.

Admitted – State Bar of California

Admitted – State Bar of Tennessee

Professional Associations

  • American Bar Association
  • Claims & Litigation Management Alliance (CLM)
  • San Diego County Bar Association
  • Federation of Defense & Corporate Counsel (FDCC)
  • National Counsel for International Riding Helmets


A highly sought-after speaker, Mr. Koska has shared his experience in groundwater litigation with a number of national and regional industry associations, including the National Association of Water Companies (NAWC), the Southeast Regional Water Purveyors Association, the National Conference of Regulatory Attorneys and the National Association of Regulatory Utility Commissioners (NARUC).

Following his presentation at the 2008 annual meeting of the NARUC Committee on Water, the NARUC Board of Directors adopted a resolution encouraging states to consider legislation or regulations that would provide a safe harbor from liability for water purveyors providing water in compliance with federal and state drinking water standards, similar to the California safe harbor confirmed by the Court of Appeal in the August 2007 case In re: Groundwater Cases.

Selected Recent Presentations

  • 31st Annual National Conference of Regulatory Attorneys, “A Safe Harbor for Water Companies: From Litigation to Legislation,” June 2008, Charleston, South Carolina
  • National Association of Regulatory Utility Commissioners Committee on Water, “A Safe Harbor for Water Companies that Comply with Safe Drinking Water Standards: State Legislation,” February 2008, Washington, D.C.   Download This Presentation
  • National Association of Water Companies, 2007 National Drinking Water Symposium, Relief From Tort Liability for Drinking Water Providers,” October 2007, La Jolla, California.
  • American States Water Company, Officers and Senior Management, “Managing Electronic Information and E-Discovery,” October 2007, San Diego, California  Download This Presentation
  • National Association of Regulatory Utility Commissioners, Staff Subcommittee on Accounting and Finance, “The Effect of Environmental Lawsuits,” September 2006, Portland, Maine.
  • Presentation of mock trial from Johnson v Spelling-Goldberg, to FDCC in Banff, Calgary, Canada in July 2015.
  • Presentation of “ A Tsunami of Rising Water Litigation “ to FDCC in Charleston, SC, March 2017.


Mr. Koska has authored articles for a variety of publications, including:

  • “From Litigation to Legislation: A Safe Harbor for Drinking Water Providers” (APWA Reporter, August 2008)
  • “Wastewater Systems in 20 States Face Serious Funding Crisis” (April 3, 2008)
  • “Unanimous Supreme Court Permits Private Parties to Sue for Cleanup Expenses Under CERCLA Section 107″ (July 11, 2007)
  • “Suing over Sewage: The Future of San Diego’s Coastal Waters” (San Diego Transcript, May 2, 2002)



Contact the firm for a free consultation.

The content of this website has been prepared by Janathan L. Allen, APC for informational purposes only and should not be construed as legal advice or tax advice. The content on this website does not create or constitute an attorney-client relationship, and readers should not act upon it without the advice of an attorney, tax attorney or legal counsel. Do not rely on published legal and tax law information as a substitute for consultation with an attorney, tax attorney, CPA and/or other professional advisors. Information contained in this website may be considered advertising. Links to websites or web pages operated by third parties are provided solely as a convenience to you. Such linked sites are not under our control and we are not responsible for the contents of any linked site or any link contained in a linked site. We make no representation or warranty and assume no liability or responsibility for other websites or web pages and/or their content.