Public Conduct in San Mateo County, CA (2026)
4 county-level rules, plus city-specific rules for 1 city in San Mateo County, California.
Verified from official government sources
Loud Party Ordinance
In unincorporated San Mateo County, hosting a loud or unruly gathering of four or more people where a minor drinks, uses cannabis, or is served alcohol triggers social-host liability and fines.
San Mateo County Social Host Liability
Significant RestrictionsSan Mateo County Ordinance Code § 3.05.030(a)
No person shall act as a Social Host, as defined in Section 3.05.020 of this chapter, of a Loud or Unruly Gathering where a Minor has possessed, consumed, or has been served any Alcohol, Alcoholic Beverage, Cannabis, and/or Controlled Substances.(b)It is the duty of any Responsible Person who knowingly hosts, permits, or allows a gathering at any public or private premises to take all reasonabl...
Loitering Rules
In unincorporated San Mateo County, it is a misdemeanor to loiter in, on, or about any building or place open to the public where alcoholic beverages are sold. The Ordinance Code separately bars drinking within 1,000 feet of such places on streets, sidewalks, or public parking lots.
Loitering Near Alcohol Sellers in San Mateo County
Some RestrictionsSan Mateo County Ordinance Code §§ 3.44.020, 3.44.030, 3.44.040
3.44.020 - Loitering near certain places prohibited. It shall be unlawful for any person to loiter in, on or about buildings and places open to the public where alcoholic beverages are sold. 3.44.030 - Loitering defined. As used in this chapter, "loiter" means to linger, wait, or delay in and about the places designated with no lawful purpose. 3.44.040 - Buildings and places where alcoholic bev...
Outdoor Smoking Restrictions
San Mateo County bans smoking, including e-cigarettes and vaping, throughout its unincorporated area and on every county-owned or leased building wherever located. Section 4.96.040(c) extends the ban into every county-owned or maintained beach, park and trail, and subsection (a) creates a 30-foot smoke-free buffer around county buildings. Fines escalate for repeat offenders.
San Mateo County Outdoor Smoking Ban
Significant RestrictionsSan Mateo County Code § 4.96.040(c)
4.96.040 - Areas where smoking is prohibited. Smoking shall be prohibited: (a)Within any enclosed structure owned or leased by San Mateo County wherever located except private residences leased from the County, which are governed by the provisions of Chapter 4.97 of this Ordinance Code; and within thirty (30) feet in any direction from any enclosed structure owned by the County, as determin...
Public Alcohol Use
San Mateo County parks generally ban liquor other than beer or wine; hard alcohol is allowed only in designated areas of Coyote Point County Park under Section 3.68.080(t).
San Mateo County Park Alcohol Rules
Significant RestrictionsSan Mateo County Ordinance Code § 3.68.080(t)
No person shall possess or consume alcoholic beverages, other than beer or wine, in any form within any County Park or Recreation area, or on the San Francisco Fish and Game Refuge. Alcoholic beverages as described herein are permitted at Coyote Point County Park only in designated areas and during designated times. No person shall possess or consume any alcoholic beverages in any form at the C...
Public Conduct by City in San Mateo County
1 cities in San Mateo County have their own public conduct rules. Each link goes to that city's dedicated page with code citations.
All San Mateo County ordinances
See every category we cover for San Mateo County: parking, noise, fences, fires, animals, pools, and more.
San Mateo County Ordinance Hub →