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Headshot of Diane Papan

Diane Papan

Democrat, State Assembly
District 21, San Mateo
Time in office:
  • Assembly: 2022-present

General Contact Info

Capitol Office

1021 O Street, Suite 4220

Sacramento, CA 95814

Capitol Office

P.O. Box 942849-0021

Sacramento, CA 94249

Phone: (916) 319-2021

District Office

1528 South El Camino Real, Suite 302

San Mateo, CA 94402

Phone: (650) 349-2200

Bio

Diane Papan’s family name has deep ties to the Assembly, though Papan herself is a relative newcomer. Her father, Lou Papan, was known as the “Dean of the Assembly” for the two decades he spent in the chamber. Papan earned a political science degree from UCLA and a law degree from the UC Hastings College of Law. Papan, 63, worked as an attorney and was mayor and city councilmember for the city of San Mateo. She chairs the Assembly Committee on Water, Parks, and Wildlife. She and her husband have one daughter.

Leader Badges

Environment Badge

Ideology

Left

Moderate

Right

Bill Activity

0

Of 37 bills:
15 Passed
9 Failed
13 Pending

For this session year, this legislator initiated 37 bills: 15 passed, 9 failed, and 13 are currently pending.

Alignment Meter

See all-time percentage of this legislator’s alignment with any organization based on total votes.

xx% votes: xx

Influence

There are three categories of donations to legislators after they are elected that encourage a working relationship between the donor and the legislator. The three categories are: 1-Gifts, 2-Travel, 3-Behests.

Giver
Value
Date
Description
Women in CA Leadership $46 Dec 5, 2022 plant/pin
Senator Bill Dodd $45 Dec 6, 2022 gift basket

Gifts

Legislators are not allowed to accept gifts of more than $10 per month from registered lobbyists. Gifts from any other single source are limited to $590 in a calendar year.

Gift Received Rating
#102/120

This legislator is ranked 102nd highest for the amount of personal gifts received.

Policy

Bills Authored by Diane Papan

AB 2595
San Mateo Electric Bicycle Safety Pilot Program.

Committee: Assembly Standing Committee on Transportation

Passed
San Mateo Electric Bicycle Safety Pilot Program. Committee: Assembly Standing Committee on Transportation
AB 2234
California Environmental Quality Act: geothermal exploratory projects.

Committee: Assembly Standing Committee on Natural Resources

Passed
California Environmental Quality Act: geothermal exploratory projects. Committee: Assembly Standing Committee on Natural Resources
AB 2296
Planning and zoning: housing element: regional housing needs allocation.

Committee: Assembly Standing Committee on Housing and Community Development

Passed
Planning and zoning: housing element: regional housing needs allocation. Committee: Assembly Standing Committee on Housing and Community Development
AB 501
Lawsuits, liens, and other encumbrances.

Committee: Assembly Standing Committee on Banking and Finance

Passed
Lawsuits, liens, and other encumbrances. Committee: Assembly Standing Committee on Banking and Finance
View All Bills

Committees

Most of the policy work in the state Capitol is done in “Standing” committees. Legislators also work on budget subcommittees. There are also “Special” and “Select” committees with a more narrow topic focus. And there are “Joint” committees with members from the Senate and Assembly.

Interest Group Rankings

Hearings

Featured Comments

Below are links to the video and transcript of recent, substantive comments by this legislator in committee hearings or floor sessions.

Preview image for AB 2469 7MIN
Aug 31, 2026

AB 2469

Data centers: water use disclosures.

Preview image for AB 2234 1MIN
Aug 31, 2026

AB 2234

California Environmental Quality Act: geothermal exploratory projects.

Preview image for AB 2619 2MIN
Aug 27, 2026

AB 2619

Water resources: data centers.

Preview image for AB 2296 49SEC
Aug 26, 2026

AB 2296

Planning and zoning: housing element: regional housing needs allocation.

Preview image for AB 1931 56SEC
Aug 26, 2026

AB 1931

Insurance: home protection companies.

Preview image for AB 2111 1MIN
Aug 26, 2026

AB 2111

Electricity: transmission planning and transmission facilities.

Preview image for AB 2380 1MIN
Aug 20, 2026

AB 2380

Pest control: registration fees.

Preview image for AB 2595 48SEC
Aug 19, 2026

AB 2595

San Mateo Electric Bicycle Safety Pilot Program.

Preview image for AB 2469 26MIN
Jul 1, 2026

AB 2469

Data centers: water use disclosures.

Preview image for AB 2234 12MIN
Jul 1, 2026

AB 2234

California Environmental Quality Act: geothermal exploratory projects.

Preview image for AB 2322 6MIN
Jul 1, 2026

AB 2322

Water discharge: commercial, industrial, or institutional sites.

Preview image for AB 2619 14MIN
Jul 1, 2026

AB 2619

Water resources: data centers.

View All Hearings

District

View of map with yellow overlay for Assembly District 21 boundaries.
District 21 is a Safe Democratic District
Democratic Party candidate has a very high likelihood of winning in an election

Previous Election (2024):

Diane Papan
73.8%
WON
Mark Gilham
26.2%

Party Registration

District: 56%, State: 47% DEMOCRAT 56% 47% District: 56%, State: 47% DEMOCRAT 56% 47%
District: 15%, State: 24% REPUBLICAN 15% 24% District: 15%, State: 24% REPUBLICAN 15% 24%
District: 24%, State: 22% NO PARTY 24% 22% District: 24%, State: 22% NO PARTY 24% 22%

Census Data

Median age 0 10 20 30

Median age