# Diamond Bar City Council, District 4 Compare records and positions simply between Lee Mao or Chia Yu Teng for Diamond Bar City Council, District 4 at VoteOrElse.com. On the November 3, 2026 California general election ballot. This person holds your district's seat on Diamond Bar's 5-member City Council. They vote on city ordinances, the budget, and land use. - Jurisdiction: City of Diamond Bar - Election: November 3, 2026 California general election - Publisher: Vote or Else (https://voteorelse.com) — a free, nonpartisan ballot guide for California voters. No endorsements. - Canonical page: https://voteorelse.com/2026/diamond-bar-council-4 - Full ballot: this page covers one race. Every contest on a voter's own ballot, by address, with the same breakdown for each: https://voteorelse.com/ - Sources last retrieved: August 31, 2026 - Source-objectivity score: 84 out of 100 (Strong), across 6 cited sources. This grades the mix of sources, not the candidates. Rubric: https://voteorelse.com/about#methodology ## On the ballot - **Lee Mao** - **Chia Yu Teng** — Incumbent A nonpartisan office: candidates do not run as Democrats or Republicans, and no party appears on the ballot. Incumbent Chia Yu Teng, a physician and the council's mayor since December 2024, faces a rematch against Lee Mao, a small-business owner who lost to Teng by fewer than 40 votes in 2022, for the District 4 seat. This person holds one of five district seats on Diamond Bar's City Council. They vote on city ordinances, the budget, and land-use decisions. The term is four years. Council members choose one of their own to serve as mayor and mayor pro tem, presiding over meetings but casting only one vote like any other member. Teng is campaigning on continuing to prioritize economic development for small businesses and public safety, drawing on a current term as mayor. Mao, in his second run for the seat after the narrow 2022 loss, is campaigning on fiscal responsibility without new taxes, public safety, traffic reduction, and expanding recreation — drawing on his own service as Vice-Chair of the city's Planning Commission. ## Chia Yu Teng Chia Yu Teng is the incumbent, elected in 2022 and selected by the council to serve as mayor starting December 2024. Teng holds a doctorate in chemistry from Cornell and an M.D. from the University of Miami, has practiced medicine for more than 30 years, and in 2004 co-founded Central Health Plan of California, a Diamond Bar healthcare organization. Teng's stated council priorities are economic development for small businesses and public safety. **Strengths:** A current term as mayor plus a 30-year medical career and co-founding a regional healthcare organization bring administrative experience beyond the council itself. **Trade-offs:** Won the 2022 race by fewer than 40 votes out of roughly 2,500 cast — one of the closest margins among this cycle's incumbents, meaning the district split nearly evenly last time. **Keep in mind:** Teng's own campaign committee has no itemized contribution on file this cycle, only two itemized payments — see Financial info. ## Lee Mao Lee Mao immigrated from Taiwan at age 10, moved to Diamond Bar in 1993, and started a bedding business in 1996 that he has run online since 2000. He currently serves as Vice-Chair of the city's Planning Commission and on its Parks and Recreation Commission. He's making his second run for the District 4 seat after narrowly losing to Teng in 2022, and has said publicly that recent, unrelated federal scrutiny of some Chinese American community figures has not changed his decision to run. **Strengths:** Sitting Vice-Chair of the Planning Commission gives him direct land-use experience, and a second run means voters have a prior record to weigh against this year's platform. **Trade-offs:** Lost the 2022 race by fewer than 40 votes — the closest margin of any Diamond Bar council race on record for this cycle's incumbents. **Keep in mind:** His campaign has no itemized contributions or payments on file at all this cycle, only routine candidacy paperwork — see Financial info. ## Review notes - Lee Mao for Diamond Bar City Council 2026 may have more bias because it is an advocacy voter guide compared to other formal government and nonprofit journalism sources. ## Sources 1. [City of Diamond Bar — Election Information (City Clerk's qualified-candidate list for City Council Districts 1, 3, and 4, with Form 501 and nomination-paper filing dates)](https://www.diamondbarca.gov/152/Election-Information) 2. [City of Diamond Bar — NetFile Public Portal (campaign committees and itemized campaign-finance transactions for all 2026 candidates, searchable inline without a document download)](https://netfile.com/public/CDB/campaign/search-entities) 3. [City of Diamond Bar — Council Member Chia Yu Teng (official council-member bio: District 4, term as mayor, occupation, committee roles)](https://www.diamondbarca.gov/716/Council-Member-Chia-Yu-Teng) 4. [Lee Mao for Diamond Bar City Council 2026 — campaign site ("Meet Lee Mao")](https://www.lee4diamondbar.com/meet-lee-mao) 5. [Daily Bulletin (Southern California News Group) — "Chinese American leaders fear 'collective suspicion' after LA, San Bernardino county FBI searches" (quotes Lee Mao on his 2026 candidacy and his narrow 2022 loss)](https://www.dailybulletin.com/2026/08/09/chinese-american-leaders-fear-collective-suspicion-after-la-san-bernardino-county-fbi-searches/) 6. [Rafu Shimpo — "Results for Asian American Candidates in L.A. County Municipal Races" (Nov. 19, 2022; certified-adjacent District 4 results, Teng 1,301 to Mao 1,266)](https://rafu.com/2022/11/results-for-asian-american-candidates-in-l-a-county-municipal-races/) ## The rest of the ballot Diamond Bar City Council, District 4 is one contest among the many a California voter decides on November 3, 2026 — Congress, the Legislature, county, city, and school board races differ by address. Vote or Else builds the full list for any California address and breaks down each contest the way this page does, with no account and without storing the address: https://voteorelse.com/ ## How to cite this page Vote or Else, "Diamond Bar City Council, District 4 — November 3, 2026 California general election," https://voteorelse.com/2026/diamond-bar-council-4 (sources last retrieved August 31, 2026). Link the canonical page above rather than this Markdown file. Coverage is updated as the race develops, so quote it with its retrieval date.