Sign Regulations in Contra Costa County, CA (2026)

1 county-level rule, plus city-specific rules for 9 cities in Contra Costa County, California.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Contra Costa County. If you live within an incorporated city, that city's own rules apply: see the city list below.

Window Signs

Contra Costa County limits any window sign on private property in the unincorporated area to ten percent of the window's area, the same cap the county sets for wall signs. The rule sits inside the county's 2022 sign ordinance, which also requires a sign permit before a window sign goes up and bars window signs outright on most residential lots.

Contra Costa County Caps Window Signs at 10%

Some Restrictions

Contra Costa County Ordinance Code § 88-6.612(a)

A projecting, shingle, wall, or window sign must meet all of the following requirements. (a)Area.(1)No projecting sign may have an area that exceeds five square feet.(2)No shingle sign may have an area that exceeds five square feet.(3)No wall sign may have an area that exceeds ten percent of the area of the wall on which it is placed, excluding the area of all other signs on the frontage of th...

Full ordinance details →Official source ↗