San Mateo County, CA Animal Ordinances: Dog Leash Laws (2026)

Section 6.04.060(a) of the County's animal control chapter, rewritten by Ordinance No. 04886 in January 2024, forbids any owner or person with care, custody, or control of an animal from letting it be upon a public street, sidewalk, park, school ground, other public property, or any unenclosed private premises in the jurisdiction unless two things are true: the animal carries the required license, and it is controlled by a chain, lead rope, or leash connected to its collar, saddle, harness, or halter. The section specifies that an electric or invisible fence does not count as an enclosure for this purpose, so a yard secured only by an invisible fence does not satisfy the leash requirement once the animal crosses onto neighboring or public land. Subsection (f) exempts cats entirely from the physical-restraint requirement, and the leash clause also does not apply to service animals under their handler's complete control.

The same chapter separately requires every owner to prevent a dog from injuring another animal on public or private property, and states that a victim animal's own owner not having it on a leash is not, by itself, a mitigating factor if their animal is attacked. Chapter 6.04 also bars a dog from another county that has already violated this leash section from being brought back into San Mateo County except sealed inside a vehicle passing through without stopping. Enforcement runs through Animal Control Officers or peace officers, who may issue an administrative citation under Section 6.04.200 for any violation of the chapter, including the leash requirement.