San Leandro, CA Public Conduct: Loud Party Ordinance (2026)

Adopted by Ordinance No. 2018-016 in 2018, Chapter 4-18 defines an "unruly gathering" as a party of 20 or more people on private property that causes a "substantial disturbance" in a neighborhood's quiet enjoyment or threatens health and safety. Section 4-18-200 lists qualifying conduct: a noise disturbance generating three or more complaints in any four-hour period, obstructing streets, public drunkenness, unlawful alcohol or drug possession, serving alcohol to minors, fights, urinating or defecating in public, fireworks, vandalism, littering, people on unauthorized rooftops, and throwing objects at responders.

Section 4-18-300 makes it unlawful and a public nuisance for any "responsible person," meaning whoever controls the property or caused the gathering, to cause or allow such a gathering; the City can order it disbanded, cite attendees, or make arrests. Section 4-18-400 separately penalizes any attendee whose own conduct contributes to the disturbance. When police respond, Section 4-18-500 requires a mailed notice to the property owner, and Section 4-18-600 makes the owner, the responsible person (or a juvenile's parents), and any contributing attendee jointly and severally liable for the City's response costs, though an owner isn't liable for uninvited guests' unforeseeable conduct if reasonable steps were taken to exclude them. A landlord who doesn't occupy the property but keeps allowing violations is guilty of an infraction under Section 4-18-700(c).