Judge Dean S. Lum (Ret.) joined JAMS in 2022 after a distinguished 23-year career on the King County (Seattle) Superior Court and serves as an arbitrator, mediator and court appointed neutral on a wide range of civil matters. As a trial judge, Judge Lum presided over hundreds of civil trials, heard thousands of civil motions and conducted dozens of settlement conferences. He has skillfully handled numerous complex personal injury, malpractice, employment, partnership dissolution/valuation, class action/mass torts, products liability and family law cases. As a judge and/or lawyer, Judge Lum gained extensive experience in complex commercial and insurance coverage and insurance bad faith cases and has been involved in many of the most significant Washington State insurance coverage cases of the past 30 years. While on the bench, he presided over dozens of bad faith, Insurance Fair Conduct Act, Consumer Protection Act and coverage cases involving claims for professional malpractice, theft, construction delays, flooding, disease and business interruption.

Prior to taking the bench, Judge Lum was a deputy prosecutor who tried over 50 felony jury trials to verdict and who was often assigned to prosecute sexual assault and harassment cases. He also served as a civil litigator for several mid-sized Seattle law firms. As a civil defense litigation attorney, his practice concentrated on insurance coverage/bad faith, construction defect, professional liability, product liability and premises liability cases. 

Judge Lum is highly regarded among counsel for his preparation; approachable demeanor; dedication to judicial and lawyer education; commitment to diversity, equity and inclusion; and ability to explain complex evidence and issues. Whether as a judge on the bench or through his involvement in civic, educational, charitable and bar association activities, he is known for his ability to calm sometimes contentious parties and find common ground and solutions to difficult problems. 

ADR Experience and Qualifications

Since joining JAMS, Judge Lum has mediated and arbitrated a wide range of civil matters, including commercial, insurance, business valuation, personal injury, estate, family law and consumer protection and regulatory matters, and has served as a Special Discovery Master, Title IX and Office of Insurance Commissioner Hearing Officer, and as a neutral evaluator.  

Representative Matters

• Business Commercial
• Mediated dispute between majority and minority partners in LLC regarding compensation, dilution of shares and alleged improper investment in real estate
• Mediated dispute between commercial landlord and condominium board over alleged misallocation of assessments and failure to make improvements
• Mediated dispute between former partners in a restaurant over alleged failure to repay investment and diversion of funds
• Mediated dispute between former partners in a family real estate trust over valuation of properties in US and China
• Mediated dispute between national health/beauty franchisor and franchisee over alleged violation of Franchise Act, fraud and alleged failure to mitigate damages
• Mediated dispute between large health care staffing providers over alleged overbilling and failure to document time spent on the job
• Arbitrated breach of contract dispute between software company and online retailer regarding pricing and alleged price fixing.  
• Arbitrated matter involving violations of the Washington Franchise Investment Act (FIPA). 
• Mediated breach of contract fee dispute between former executive and employer over credit for future project 
• Mediated breach of contract matter related to costs associated with tenants relocating pending completion of a new building. 
• Mediated business partnership formation dispute over a nursing business 
• Arbitrated business dispute between partners on allocation of damages upon business failure 
• Class Action & Mass Tort
• Arbitrated mass commercial case involving national dispute over fees charged to retailers by a credit card company
• As a judge, class action case where plaintiff alleged that national retailer was vicariously liable for the actions of third-party vendors advertising on its website
• As a judge, class action case involving customers alleging that a medical provider failed to protect their privacy through use of certain vendors on that provider’s website
• As a judge, class action case alleging national online retailer failed to provide refunds in a timely manner during the pandemic
• As a judge, class action case alleging medical provider failed to provide a safe environment for patients due to alleged faulty HVAC system  
• Arbitrated mass commercial case involving national dispute over termination of franchisor’s right to expansion and valuation of loss of business opportunity 
• Arbitrated mass commercial case involving alleged consumer pricing violations by a national retailer 
• Construction
• Mediated dispute involving the construction of two large affordable housing complexes over allegations of over-billing and compensation formulas
• Mediated dispute involving WA Underground Utility Damage Prevention Act. 
• Mediated dispute over mechanic’s lien between condo association and construction company. 
• Mediated dispute regarding additional payments allegedly owed to contractor 
• Mediated dispute between general contractor and large commercial project owner regarding allocated overhead and other excess costs 
• Construction Defect
• Mediated dispute where contractor agreed that it had caused delays to a landlord’s large apartment project but the parties could not agree on appropriate compensation for that delay.
• Mediated dispute between contractor and developer over whether the scope and details of the project where illegal and/or permissible under municipal codes.
• As a judge, water infiltration case at large, 10-building apartment complex involving allegations that the general contractor had failed to coordinate trades and to properly supervise the staging/timing of subcontractor work  
• As a judge, dispute between general contractor and municipality over alleged improper installation of utility lines and, conversely, allegedly unclear direction and multiple change orders delaying completion
• As a judge, dispute between general contractor and remaining subcontractors when one subcontractor became insolvent at a large condominium project
• As a judge, dispute between general contractor and utility over construction delays and change orders at a large water utility project  
• Mediated dispute over tenant’s abandonment of property mid-way through lease period 
• Employment Law
• Mediated numerous employment breach of contract cases 
• Arbitrated and mediated multiple employment discrimination and retaliation matters 
• Mediated Green Economy case involving scope and viability of non-compete agreements by high level executives of an industrial emissions control company who went to work for competitor.
• As a judge, sexual harassment, failure to protect and failure to properly investigate case involving two employees of a national retailer, where an alleged mishandled initial investigation led to further documented harassment
• As a judge, wage and hour case involving allegations that local machine manufacturing plant failed to pay overtime and provide meal/rest breaks. Resolution of local case served as template for settlement of claims at other plants nationwide
• As a judge, dispute involving a top car salesperson, a noncompete clause and his access to customers and sales lists when one dealership hired him away from another
• As a judge, wage and hour case involving undocumented restaurant workers, failure to pay overtime due to blended rates and alleged failure to keep records
• As a judge, noncompete clause cases involving software, pharmaceutical, realty and IT salespersons/executives and whether geographical, subject matter and/or time limits could be enforced and/or rewritten  
• Arbitrated several consumer cases against auto dealerships for breach of contract, warranty, and violation of Consumer Protection Act claims 
• Mediated wrongful termination/failure to engage in progressive discipline case involving municipality 
• Estate Probate Trusts
• Mediated complex dispute pending in several jurisdictions over donative intent and valuation of artwork and real estate
• Mediated and arbitrated matter involving alleged breach of fiduciary duty by siblings acting personal representatives/trustees 
• Mediated dispute involving valuation and division of interest in vacation home 
• Family Law
• Mediated numerous dissolution cases involving divisions of assets and parenting plan and child support.
• Mediated modification case where parties initially agreed to a relocation but were having challenges with the exchange following new job hours and responsibilities for both parents.
• Mediated Parenting Plan dispute involving incorporation of spouse into child’s life after commissioner had not imposed restrictions and involving significant cultural differences between the parents.
• Mediated dissolution case where main dispute was valuation of property, including vintage motorcycles.
• Mediated mid-term marriage dissolution case where chief disputes were valuation of one spouses’ business and alleged hidden assets.
• As a judge, contentious valuation and asset award case involving assets and real estate in a foreign country that does not enjoy full diplomatic relations with the U.S., greatly complicating discovery and depositions
• As a judge, high-profile family involved in disagreement over language education and timing for relocation of one spouse
• As a judge, numerous family law cases involving real estate, stock option and business valuation, including evaluation of comparable homes, cost of sale, market conditions, goodwill and timing considerations  
• Higher Education & Title IX
• Judge Lum completed JAMS Internal Title IX Training. As a prosecutor Judge Lum spent over 4 years on the Special Assault Unit prosecuting sexual harassment, domestic violence and sexual assault cases and presided over numerous jury trials and hearings in this area as a trial judge. He has been involved in higher education policy for many years as Trustee and Presidential Community Advisory Council Chair for one of the largest community college systems and one of largest universities in the country.
• Retained to serve as a hearing officer in Title IX matters for a large private university and attended that institution’s in-house training. Handled numerous administrative hearings involving allegations of sexual misconduct, sexual harassment, and dating violence
• Insurance
• Mediated dispute concerning environmental remediation work of a city-owned property 
• Mediated complex allocation dispute involving insurers of a manufacturer and a municipality arising out of a wrongful death suit 
• Mediated first party insurance bad faith case 
• Mediated underinsured motor vehicle accident 
• Served as Presiding Hearing Officer for the Office of the Washington State Insurance Commissioner, presiding over numerous insurance agent and broker license revocation and penalty matters
• Arbitrated UIM dispute where respondent disputed the nature and extent of injuries and disputed whether any injury occurred at all.
• As an attorney, litigated first party, 3rd party and DIC insurance coverage cases over natural resource and CERLCA/MTCA claims for gradual groundwater contamination and soil cleanup, and has particularized knowledge of duty to defend, excess layer, exhaustion and allocation issues
• As a judge, first- and third-party property insurance dispute involving extensive water damage to a business due to unusual rainfall and construction on the adjacent property
• As a judge, first-property, third-property and difference-in-conditions insurance dispute with chemical manufacturer for state natural resources claim where manufacturer had previously litigated and received coverage for federal cleanup liability  
• As an attorney, numerous third-party liability cases by corporate policyholders accused of gradual groundwater pollution from manufacturing, disposal and/or chemical storage against layers of primary and excess insurers, often spanning decades and often involving the known loss/fortuity doctrine, policy exclusions and allocation of settlement proceeds and/or recovery
• As a judge, numerous bad faith, IFCA and Consumer Protection Act cases against insurers by policyholders seeking coverage for construction delays, flooding, disease, stolen property, construction delays and business interruption  
• Personal Injury
• Mediated personal injury case against a municipality and a corrections organization over sexual harassment and failure to supervise
• Mediated UIM personal injury/bad faith case involving extent of non-economic damages
• Arbitrated personal injury/product liability case involving augmented reality 
• Mediated premises liability matter that occurred at county jail facility 
• Mediated premises liability case involving steel pipes at a job site 
• Mediated serious pedestrian injury case due to alleged negligent road design and improper placement of barriers by municipality 
• Mediated case involving damages arising out of injuries suffered by cruise vessel customer 
• Arbitrated medical malpractice case involving alleged improper pain management 
• Mediated personal injury case against a municipality and corrections officers where inmate was allegedly injured through excessive use of force in the booking process.
• Mediated on the job injury where claimant alleged crushing injuries from a pipe giving rise to significant medical bills, pain and suffering and future lost income.
• Successfully mediated auto collision case where minor plaintiff received eye injury following collision with a police cruiser, complicated by disagreement in valuation between plaintiff’s counsel and minor’s guardian ad litem
• As a judge and an attorney, numerous wrongful death/product liability cases arising out of asbestos exposure and mesothelioma/multiple myeloma, often spanning decades involving multiple employers and/or sites and multiple defendants
• As a judge, product liability/wrongful death case involving crash in foreign country and over 300 decedents, giving rise to novel jurisdiction, choice of law and forum non conveniens issues
• As a judge, multiple vehicle collision cases involving up to six vehicles, giving rise to complicated causation and apportionment of fault issues
• As a judge, products and premises liability case where golfer suffered compound fracture resulting in over $130,000 in medical costs after slipping on wet golf course, and sued the course, the golf shoe manufacturer and the spike manufacturer  
• Professional Liability
• Arbitrated legal malpractice and failure to pay attorneys’ fees dispute arising out of a large federal criminal fraud case.
• As a judge, dental malpractice case where dentist was alleged to have improperly scraped excess layers from teeth, causing permanent tooth loss, pain and disfigurement
• As a judge, medical malpractice case where surgeons left instruments inside patient, leading to infection and multiple corrective surgeries
• As a judge, medical malpractice case where hospital and doctor were accused of exceeding the scope of permission granted for care and failing to follow best practices for informed consent for surgery
• As a judge, legal practice action against attorney and a national public interest nonprofit organization by client who rejected large settlement offer obtained for him and who then lost at trial, based on alleged improper advice and assurances  
• Real Property
• Mediated dispute over scope of easement and fair market value for parking for a utility’s vehicles
• As a judge, numerous eminent domain cases where governmental agency takes property for transit projects and primary issue was real estate valuation
• As a judge, real estate boundary dispute cases between neighbors, often involving adverse possession claims, old fence lines, conflicting survey results and historical documents
• As a judge, cases involving failure to record and/or lost deeds and improper reliance on electronic records, giving rise to disputes between banks, brokers and property owners
• As a judge, case involving alleged misrepresentation by seller, and dispute over commission and whether broker was seller’s or buyer’s agent  
• Special Discovery Master/Court-Appointed Neutral
• Served as Special Discovery Master/Court Appointed Neutral in state and federal courts
• Cannabis
• Mediated civil forfeiture case involving houses involved in marijuana grow operations where owner argued that the municipality’s requested forfeiture was excessive.
• As a judge, numerous cannabis partnership/business dissolution cases involving complex valuation and division of assets, inventory and goodwill
• As a judge, several regulatory litigation cases involving the State of Washington and allocation of licenses to various cannabis businesses  

Honors, Memberships, and Professional Activities

Selected Awards and Honors

Selected Speaking Engagements

Selected Memberships, Affiliations and Professional Activities

• Board President, Washington Courts Historical Society, 2025
• Commissioner, ABA Commission on Law and Aging, 2024-2025
• Washington State Co-Chair, Fellows of the American Bar Foundation, 2024-2025 
• Board Member, YWCA of Seattle/King County, 2023-2025
• Board Member/Vice Chair, Chinese Information and Service Center, 2023-2025   
• Board Member, ABA Coalition on Racial & Ethnic Justice, 2021–2024
• Board Member/Former Chair, University of Washington President’s Minority Community Advisory Council, 2014–2025
• Board Member, ABA Council for Diversity in the Educational Pipeline, 2018–2021
• Commissioner, ABA Commission on Immigration, 2013–2017
• Trustee, Washington State Superior Court Judges’ Association, 2013–2016
• Life Fellow, American Bar Foundation, 2011–2025
• Founding President, Asian Bar Association Student Scholarship Foundation, 2011
• Board Member, ABA Division on Public Education, 2001–2004
• Chair, Washington and King County National Adoption Day Celebration, 2001–2021
• Member, ABA House of Delegates (Representing King County Bar Association), 1998–2003
• Member/Vice Chair, Board of Trustees, Seattle Community College District, 1996–1998
• Chair, Ethnic Diversity in the Legal Profession Committee, King County Bar Association, 1995
• Trustee, King County Bar Foundation, 1992–1994
• President, Asian Bar Association of Washington, 1992
• Member, King County Bar Association, 1983–2025   
• Member, Washington State Bar Association, 1983–2025 (judicial status 1998–2022)
• Former Member, Defense Research Institute and Washington Defense Trial Lawyers

Background and Education

• Judge, King County Superior Court, 1998–2022
  • Assistant Presiding Judge, 2020
  • Chief Criminal Judge, 2016–2017
  • Chief Civil Judge, 2004–2006
  • Chief Judge, Regional Justice Center, 2003–2004
• Dean, Washington State Judicial College, 2004
• Faculty, Washington State Judicial College, 2006–2018
• Faculty, National Judicial College, 2010
• Adjunct Professor, Seattle University School of Law, 2006–2022
• Of Counsel, Bullivant Houser Bailey, 1997–1998
• Founding Shareholder, Forsberg & Umlauf, 1993–1997
• Associate; Bradbury, Bliss & Riordan; 1990–1993
• Deputy Prosecuting Attorney, King County Prosecutor’s Office, 1983–1990
• J.D., University of Washington School of Law, 1983
• B.A., Pomona College, 1980