Contra Costa County, CA Animal Ordinances: Breed Restrictions (2026)

Contra Costa County follows California's statewide dangerous-dog framework (Food & Ag Code §§31601–31683). A dog can be declared 'potentially dangerous' after two unprovoked biting/aggressive incidents within 36 months, or 'vicious' after causing severe injury or death, or if previously declared potentially dangerous and owner failed required measures. Declarations are made by Contra Costa Animal Services after an administrative hearing; the owner has the right to appeal. A potentially-dangerous dog must be kept indoors or in a securely enclosed yard, and when off-property must be leashed and muzzled. A vicious-dog declaration can result in destruction of the animal or strict long-term containment, signage, liability insurance, and tagging requirements. California Food & Agricultural Code §31683 explicitly preempts all breed-specific legislation — Contra Costa County has no breed ban and cannot impose one. Narrow exceptions under Health & Safety Code §122331 allow breed-specific mandatory spay/neuter programs only. Failure to comply with a dangerous-dog declaration is a misdemeanor and can result in criminal charges if the dog injures another person.