Candidates for California State Board of Equalization — District 4
2026 Primary Election — June 2, 2026
Office: State Board of Equalization (BOE) District 4 — one of five seats on the nation's only publicly elected tax assessment agency. The BOE advises county assessors, sets the taxable value of property owned by utilities and railroads, and hears taxpayer appeals. District 4 covers Southern California: portions of San Bernardino County, all of Orange County, Riverside County, San Diego County, and Imperial County. Incumbent Mike Schaefer (D) is term-limited and running for Congress. California uses a top-two primary — all candidates appear on one ballot; the top two advance to November 3.
Tom Umberg Dem Age 71 Front-runner
State Senator, SD-34 • Orange County
Current State Senator representing the 34th District (Orange County). Served previously in the State Assembly. Small businessman and attorney. Author of the "No Kings" law to prevent Trump from appearing on CA ballot for an unconstitutional third term. One of the most endorsed candidates in the 2026 cycle — backed by Gov. Newsom, Sen. Adam Schiff, Sen. Barbara Boxer, AG Rob Bonta, Speaker Rivas, Senate Pro Tem Limon, and virtually the entire Democratic establishment. Endorsements also include Congressmembers Lou Correa, Derek Tran, Juan Vargas, Dave Min, Mike Levin, Robert Garcia, Linda Sanchez, and nearly every Democratic state senator and assemblymember. Major labor backing. Leading fundraiser in the race with strong institutional support.[1]
Top Issues / Platform
- Independence & accountability: Ensure BOE decisions are free from donor or political pressure; create clear process for investigating improper influence
- Taxpayer fairness: Ensure working families and small businesses get equal consideration as corporate stakeholders
- Transparency: Make public comment meaningful and accessible; publish BOE proceedings and decisions
- Anti-corruption: Refer credible allegations of assessment influence-peddling to law enforcement
- Property tax fairness: Oversee county assessors to ensure uniform, equitable valuations[2]
Key Endorsements
- Gov. Gavin Newsom
- U.S. Sen. Adam Schiff
- U.S. Sen. Barbara Boxer (ret.)
- Attorney General Rob Bonta
- Speaker Robert Rivas
- Senate Pro Tem Monique Limon
- California Labor Federation
- SEIU-UHW
- California Young Democrats
- San Diego County Democratic Party
- 10+ Congressmembers, nearly every state Dem legislator
- Mayor Todd Gloria (San Diego)[1]
Strengths ▲
- Unmatched endorsement list — virtually the entire Democratic establishment is behind him
- Strongest name ID in the district from years in the Legislature and media presence
- Leading fundraising — clear financial advantage over all other candidates
- Legislative record provides substance for the campaign (authorship of major bills)
Weaknesses ▼
- Deep field of three Democrats splitting the vote could prevent a top-two finish if non-Umberg Dems pull 30%+
- Senate district covers part of Orange County but BOE District 4 spans 5 counties — less known outside OC
- Background as career politician may be a liability in a downballot race
- Some may question using a low-visibility BOE seat as a landing pad after legislative term limits
Cody Petterson Dem Age 50 Strong Contender
Chief Deputy, BOE District 4 • San Diego
Currently serves as Chief Deputy to outgoing incumbent Mike Schaefer on the BOE Fourth District. PhD in Anthropology from UC San Diego; BA from UC Berkeley. Senior Advisor for Land Use, Education, and Environment to San Diego County Supervisor Terra Lawson-Remer. Lecturer in UCSD Anthropology Department. Former President of San Diego Unified School Board — helped balance budgets and led approval of 2,800+ units of affordable teacher housing (tripling the state total). Founding Chair of San Diego Regional Housing Finance Authority. Fluent in Spanish. Has half a decade of experience inside the BOE — already helps oversee $167B in annual corporate property assessments. Endorsed by outgoing incumbent Mike Schaefer: "He knows the job inside and out and can hit the ground running." San Diego County Democratic Party co-endorsement. Has received labor support from Western States Carpenters PAC.[3]
Top Issues / Platform
- On-the-job experience: Already does the job as Chief Deputy — knows BOE operations, assessment process, and taxpayer appeals
- Utility oversight: Ensure utilities pay fair share for public education and other services funded by property taxes
- Housing: Leverage BOE to spur housing production and preservation for working families
- Middle class: Make tax system work for working families, not just corporate interests
- Infrastructure & schools: Direct assessment revenue to rebuild infrastructure and reinvest in schools[4]
Key Endorsements
- Incumbent Mike Schaefer (D) — outgoing BOE member
- San Diego County Democratic Party (co-endorsement)
- Western States Regional Council of Carpenters PAC
- Numerous San Diego elected officials[3]
Strengths ▲
- Uniquely qualified — only candidate with hands-on BOE experience; knows the job better than any competitor
- Schaefer endorsement is the single most powerful signal of readiness for this specific role
- Strong San Diego base in a district where SD County is the largest population center
- Housing authority and school board leadership provide concrete accomplishments to campaign on
Weaknesses ▼
- Less name ID than Umberg across the five-county district
- Third Democrat splitting the vote — Umberg's establishment support may consolidate party leaders
- Campaign fundraising likely trails Umberg significantly (carpenter PAC contributions suggest limited war chest)
- Academic background (PhD in Anthropology) does not scream "tax assessment expert" despite actual BOE experience
Martin Arias Dem Age 34 Challenger
Taxpayer Advocate • San Diego
Born and raised in San Diego. First-generation American, son of Mexican immigrants. First in his family to graduate from college — BA in Political Science from San Diego State University (2015). Serves as Taxpayer Advocate at the San Diego County Assessor/Recorder/County Clerk's Office. Has helped thousands of taxpayers lower their property taxes, assisted 20,000 disabled veterans receive property tax exemptions, and delivered $35M in tax savings for veterans and families. Previously served as Director of Prevention and Intervention Programs at San Diego County DA's Office. Former Legislative Aide in the California State Senate. Also a Trustee on the San Ysidro Elementary School District Board. Serves as Board Member of Border View YMCA and Treasurer of Imperial Beach Neighborhood Center. San Diego County Democratic Party co-endorsement.[5]
Top Issues / Platform
- Property tax relief: Expand exemptions for veterans, seniors, and working families
- Taxpayer advocacy: Use BOE to ensure county assessors treat taxpayers fairly
- Veterans' benefits: Expand awareness and access to property tax exemptions for disabled veterans
- Education funding: Ensure utilities and corporations pay fair share for public schools
Strengths ▲
- Direct property tax experience as Taxpayer Advocate — helped deliver $35M in tax savings
- Strong San Diego community ties: YMCA board, school board, neighborhood center treasurer
- First-gen American story and young age (34) bring fresh perspective to a staid office
- Bilingual (Spanish/English) in a heavily Latino district
Weaknesses ▼
- Crowded three-way Democratic primary makes it very hard to advance with votes split
- Less institutional support than Umberg or Petterson
- Youngest candidate in the race — experience level questioned for a complex tax oversight role
- Campaign fundraising likely limited; name ID low outside San Diego tax circles
Denis Bilodeau Rep Age ~55 Top Republican
Orange City Councilmember / Civil Engineer • Orange
Licensed Civil Engineer, UC Irvine graduate. Serves as Orange City Councilmember (District 4) and President of the Orange County Water District. President of the Orange Taxpayers Association — leads efforts to hold government accountable and expose waste. Has deep water resources expertise: helped expand the Groundwater Replenishment System to 130M gallons/day, initiated a groundwater cleanup project in north Orange County, and recovered millions from polluters. Endorsed by the California Republican Party, Reform California, Imperial County Republican Central Committee, and Republican Party of Orange County. Trained in water resources engineering, brings a technical/analytical approach to the BOE.[6]
Top Issues / Platform
- Taxpayer watchdog: Hold government accountable for taxpayer dollars; expose waste
- Property tax equity: Ensure fair assessments across five-county district
- Prop 13 defense: Guard against erosion of property tax protections
- Technical expertise: Apply engineering/analytical lens to tax assessment oversight
Strengths ▲
- Only Republican with significant elected experience — CA GOP endorsement solidifies party base
- Civil engineering background provides analytical credibility for a tax oversight role
- Orange County base (CA GOP heartland) in a district where OC is a major population center
Weaknesses ▼
- BOE District 4 is heavily Democratic (covers Dem-leaning SD, Imperial, parts of OC/SB)
- No Republican has won a statewide BOE race in California in the current political environment
- Less name ID outside Orange County water/taxpayer circles
- BOE experience: no direct property tax assessment background
No photo available
Gardner C. Osborne Lib Age ~55 Long Shot
Enrolled Agent / Tax Accountant • San Diego
Background
25-year tax accountant (Enrolled Agent) and Investment Advisor. Managing Member of Gardner Tax & Financial, LLC since 2000. Former Chair and Treasurer of the San Diego Libertarian Party. Has spent decades representing taxpayers on income, property, and sales tax issues — always on the side of the taxpayer. Top priorities: 1) State tax watchdog, 2) Save Prop 13, 3) Housing affordability. Endorsed by the Libertarian Party of California. Describes the BOE role as overseeing county tax assessors to confirm equal tax values, along with liquor licenses, insurance, and railroad property valuations.[7]
Top Issues / Platform
- Tax watchdog: Audit money flow and advocate for taxpayers over the state
- Prop 13 protection: Defend property tax limits against legislative erosion
- Housing affordability: Reduce tax barriers to housing development
- Waste reduction: Cut wasteful state spending that drives up tax burdens
Race Summary & Outlook
A competitive three-way Democratic primary with the establishment favorite facing a uniquely qualified insider and a rising young advocate. Key dynamics:
- Tom Umberg (D) is the clear front-runner with endorsements from Newsom, Schiff, Boxer, Bonta, nearly every Democratic legislator, and major labor unions. His legislative network and fundraising should carry him to a top-two finish.
- Cody Petterson (D) is the most uniquely qualified candidate for this specific job — he's been doing it for 5 years as Chief Deputy to the outgoing incumbent. The Schaefer endorsement is powerful but he faces an uphill battle against Umberg's institutional machine.
- Martin Arias (D) offers a compelling first-gen American story and direct property tax experience but struggles for oxygen in a three-way Democratic race.
- Denis Bilodeau (R) has the CA GOP endorsement and is the only Republican with elected experience. He's positioned for a top-two finish if the Democratic vote splits three ways — a real possibility in a downballot race with low voter attention.
- Gardner Osborne (L) is a long-shot Libertarian with tax expertise but negligible campaign infrastructure.
Likely top-two: Umberg is almost certain to advance. The second spot depends on whether Bilodeau can consolidate Republican voters (the district is heavily Democratic but three Dems could split 60% of the vote) or whether Petterson or Arias breaks through. The most conventional outcome is Umberg vs. Bilodeau, but Umberg vs. Petterson is very possible if Democratic turnout is high.
Primary: June 2, 2026 — General: November 3, 2026