California Penal Code Section 370 is the statute that defines what counts as a public nuisance under California criminal law. On its own it sets no penalty; it draws the line between ordinary annoyances and conditions serious enough to prosecute. Paired with Penal Code Sections 372 and 373a, maintaining a public nuisance is a misdemeanor punishable by up to six months in county jail, a fine of up to $1,000, or both, and every day the nuisance continues after written notice can be charged as a separate offense.
What Counts as a Public Nuisance Under Section 370
Section 370 defines a public nuisance as anything that is harmful to health, indecent, offensive to the senses, or that blocks the free use of property in a way that interferes with the comfortable enjoyment of life or property by an entire community, neighborhood, or a significant number of people. It also covers anything that unlawfully obstructs the normal use of navigable waterways, public parks, streets, or highways.1California Legislative Information. California Penal Code 370
In practice, the statute reaches a wide range of conduct. Persistent foul odors from a property. Loud machinery running at all hours. Illegal dumping that creates health hazards. Smoke or chemical emissions drifting into a residential area. Physical obstructions that block a public road or sidewalk.
The operative phrase is “comfortable enjoyment of life or property.” Courts use it to measure whether a condition has crossed from irritating to legally actionable. A barking dog that bothers one person for an afternoon probably does not qualify. A commercial operation generating toxic fumes that sicken a neighborhood for weeks almost certainly does.
How Many People Must Be Affected
A nuisance is only “public” if it reaches beyond a handful of individuals. Section 370 requires that the condition affect an entire community, a neighborhood, or at least a considerable number of people.1California Legislative Information. California Penal Code 370 A dispute between two neighbors over a fence or a tree typically belongs in private nuisance territory, not criminal court.
California Civil Code Section 3480 adds an important clarification: a nuisance remains public even if the harm is not felt equally by everyone.2Justia Law. California Civil Code 3480 Residents near a contaminated site may develop serious health problems while others a few blocks away only notice an unpleasant smell. The condition still counts as a public nuisance because it originates from a single source and radiates across the area. What matters is the breadth of the affected population, not uniform severity.
Penalties for Maintaining a Public Nuisance
Section 370 defines the offense; Section 372 supplies the criminal penalty. Anyone who maintains or commits a public nuisance, or who deliberately fails to carry out a legal duty to remove one, is guilty of a misdemeanor.3California Legislative Information. California Penal Code 372 Because Section 372 does not set its own punishment, the default misdemeanor sentence under Penal Code 19 applies: up to six months in county jail, a fine of up to $1,000, or both.4California Legislative Information. California Penal Code 19
A conviction also creates a misdemeanor criminal record, which can affect employment, housing applications, and professional licensing. For many defendants that lasting record is a heavier consequence than the jail time or fine.
Daily Offenses After Written Notice
Penal Code 373a is where penalties can multiply quickly. Once a property owner or occupant receives written notice from a health officer, district attorney, city attorney, or city prosecutor to remove or stop the nuisance, every day the nuisance continues counts as a separate misdemeanor offense.5California Legislative Information. California Penal Code 373a A property owner who ignores a notice for 30 days could theoretically face 30 separate misdemeanor counts, each carrying its own potential jail time and fine.
Section 373a also imposes a duty on prosecutors. The district attorney or city attorney is required to continuously prosecute anyone violating the section until the nuisance is fully removed.5California Legislative Information. California Penal Code 373a Ignoring the notice does not make the problem go away. It makes it exponentially worse.
Who Can Be Charged
Section 373a is not limited to property owners. It covers anyone who “maintains, permits, or allows” a public nuisance on property they own, and it also reaches anyone occupying or leasing another person’s property who lets a nuisance persist there.5California Legislative Information. California Penal Code 373a Tenants and landlords can both face charges if either one allows the condition to continue after notice.
Common Defenses
Not every unpleasant condition supports a valid public nuisance charge. Several defenses recur in these cases.
- One-time event. A public nuisance typically involves an ongoing or recurring condition. A single isolated incident, like a one-night party, usually falls short. Prosecutors need to show the condition happens regularly or leaves a lasting effect.
- Too few people affected. If the alleged nuisance bothered only a couple of individuals rather than a neighborhood or community, it does not meet the “considerable number of persons” requirement in Section 370. The complaint might support a private nuisance claim, but not a criminal charge.
- No written notice. A charge under Section 373a requires that the defendant received reasonable written notice from a health officer, prosecutor, or city attorney. Without proof that notice was properly served, the daily-offense provision cannot apply.
- Compliance with regulations. If a business operates within all applicable permits and zoning rules, that compliance can weigh against a finding that the activity constitutes a nuisance, though it is not an automatic shield.
Civil Abatement and Lawsuits
Criminal prosecution is only one of three paths California law provides. Civil Code Section 3491 lists all three: criminal prosecution, a civil lawsuit, or abatement.6California Legislative Information. California Civil Code 3491 A criminal charge under Section 370 can arrive alongside a civil action, not instead of one.
Under Code of Civil Procedure Section 731, a district attorney, county counsel, or city attorney can file a civil suit in the name of the people of California to abate a public nuisance, typically seeking an injunction ordering the responsible party to stop the activity or remove the condition. A private person whose property or personal enjoyment has been harmed by the nuisance can also sue, but must show harm that is different in kind from what the general public experiences, not just the same inconvenience shared by everyone else.7California Legislative Information. California Code of Civil Procedure 731 If a defendant ignores an injunction, contempt of court penalties follow. In some cases the local government arranges for contractors to clean up the property directly and recovers the cost through a lien.