Does Monterey County, CA have its own adu rules ordinance?

No. Monterey County, CA does not appear to have a local adu rules ordinance, California state law applies instead. The rules summarized on this page come from Cal. Gov. Code §65852.2 (ADU Law).

Key Facts Ordinance Text Full Breakdown Violations FAQ Sources More in Monterey County

Monterey County, CA Accessory Structures: ADU Rules (2026)

Some Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified June 2026

ADU rules in Monterey County, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Max ADU size (inland): 1,200 sq ft (section 21.06.372 / 21.64.030)
Max JADU size: 500 sq ft
Detached ADU height: Up to 16 ft (Use Permit if higher)
Side/rear setback: Minimum 4 ft
Coastal ADU update: Effective Dec 19, 2025; ~1,000 sq ft
Units allowed: 1 ADU + 1 JADU per single-family lot

ADU Eligibility Quick-Check

An Accessory Dwelling Unit (ADU) is a smaller, independent living unit on the same lot as a single-family home: converted garages, detached cottages, basement or attic conversions, and attached additions all qualify. Most states have streamlined ADU permitting since 2020, but local rules still control size, height, and setback.

Is your lot zoned single-family or multi-family residential?
Does your lot have at least 1,200 sq ft of buildable space?
Is your existing home owner-occupied (in most states this is not required, but some require it for ADU permits)?
Will the ADU stay under your state's size cap (commonly 850-1,200 sq ft for detached)?
Can you provide one off-street parking space (waived in many states within 0.5 mi of transit)?

If you answered 'yes' to most of these, you likely qualify in California under recent ADU streamlining laws. The Monterey County, CA rules below cover local size, height, and setback requirements.

Summary

Unincorporated Monterey County permits one ADU plus one JADU on lots with a single-family dwelling. Inland (Title 21, section 21.64.030) ADUs may not exceed 1,200 sq ft; JADUs max 500 sq ft. Detached ADUs default to a 16-ft height limit. State ADU law (Gov. Code 65852.2/66310+) preempts local rules where they conflict.

City-specific rules exist: Salinas has its own adu rules rules that differ from Monterey County's county-level regulations. If you live in Salinas, check the city-specific page instead.

Side and rear lot line setbacks for ADUs shall be a minimum of four (4) feet and shall also be sufficient for fire and safety... ADUs shall not exceed 1,200 square feet. JADUs shall not exceed 500 square feet. An ADU detached from the principal dwelling shall be subject to the height regulations for a habitable accessory structure or allowed to be up to 16-feet in height, whichever is greater.

Source: Cal. Gov. Code §65852.2 (ADU Law)View official code

Full Breakdown

030) and the Coastal Zone (Title 20). 372 defines an ADU as not exceeding 1,200 sq ft) and junior ADUs (JADUs) to 500 square feet. 22 (now also reorganized under Gov. ), supplemented by local standards; where local rules conflict with state law, state law controls. A detached ADU is allowed up to 16 feet in height (or the district's accessory-structure height, whichever is greater); exceeding 16 ft requires a Use Permit. Side and rear setbacks are a minimum of 4 feet. The County ministerially approves qualifying ADUs/JADUs.

Units on private wells or septic require Environmental Health review for adequate water and sewage. In the Coastal Zone, a November 18, 2025 ordinance (effective December 19, 2025) raised the coastal ADU size limit (reported up to 1,000 sq ft) and removed Big Sur's prior 50-unit cap, after California Coastal Commission approval.

Violations & Fines

ADUs built without required ministerial approval, Environmental Health clearance, or a building permit are subject to Monterey County code enforcement. ADUs may not be rented for 30 days or less (no vacation rental) and may not be sold separately from the primary dwelling.

Frequently Asked Questions

How big an ADU can I build in unincorporated Monterey County?

In the inland (non-coastal) zone, an ADU may not exceed 1,200 square feet and a JADU may not exceed 500 square feet, per Monterey County Code sections 21.06.372 and 21.64.030. The Coastal Zone has its own Title 20 limits, updated effective December 19, 2025 (reported up to 1,000 sq ft).

Does California state law override Monterey County's ADU rules?

Yes. The county ordinance states it applies Government Code sections 65852.2 and 65852.22 (ADU/JADU law, also under Gov. Code 66310 et seq.), and that in the event of a conflict between state ADU law and the county section, state law controls.

Sources & Official References

Other rules in Monterey County

Shed & Carport RulesSome Restrictions ADU Owner OccupancySome Restrictions Garage ConversionsSome Restrictions ADU Rental RestrictionsSignificant Restrictions Parking Rules: EV ChargingSome Restrictions Animal Ordinances: Veterinary Clinic ZoningSignificant Restrictions Animal Ordinances: Pet Groomer RulesSignificant Restrictions Fire Regulations: Smoke DetectorsSignificant Restrictions Landscaping Rules: Rainwater HarvestingLight Restrictions Landscaping Rules: Native PlantsSome Restrictions

All Monterey County rules

How Monterey County compares: Easiest Cities to Build an ADU·California rules heatmap·Compare Monterey County to another location·View the California accessory structures overview

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ADU Rules in Cities Across Monterey County

Salinas, CA