Skip to main content
CityRuleLookup

San Mateo County, CA Environmental Rules: Coastal Development (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

LCP Certified
Yes, since 1981
Zone Extent
Devil's Slide to SCZ line
CDP Required
Most new development
ESHA Buffer
100 ft from sensitive habitat
Appeals
To CCC in appealable areas

Summary

San Mateo County administers its own certified Local Coastal Program (LCP) and issues Coastal Development Permits (CDPs) for projects in the Coastal Zone, which covers roughly 240 sq miles from Devil's Slide south through Pescadero, Año Nuevo, and the Santa Cruz County line. Projects in the Coastal Zone typically require a CDP from County Planning; certain appealable areas (near the shoreline, in sensitive habitat, or in rural areas) can also be appealed to the California Coastal Commission. ESHA (Environmentally Sensitive Habitat Area) buffers, public access, and view corridors are key LCP policies.

These county ordinances apply to unincorporated areas of San Mateo County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

Coastal Act of 1976). PRC Section 30103(b) directed the Coastal Commission to prepare and adopt more detailed 1:24,000 scale Coastal Zone Boundary (CZB) maps, which occurred March 1, 1977. These 161 adopted maps provide the official basis for all other representations of the landward CZB. The digital version of the CZB created by developing this data is a conformed copy of the official boundary, and in some locations reflects legislative changes and Coastal Commission minor adjustments adopted from time to time since March 1977. Limitations of Use: The boundary depicted in the attached file ('s) was digitized from the official 1:24,000 scale Coastal Zone Boundary maps, however, there are sev

Source: SMC Local Coastal ProgramView official code

Full Breakdown

Under the California Coastal Act of 1976, San Mateo County was certified to issue its own CDPs via its Local Coastal Program (LCP), originally certified in 1981 and amended since. The Coastal Zone in San Mateo County extends from Devil's Slide in the north through Pacifica (except where Pacifica has its own LCP), Montara, Moss Beach, Princeton, El Granada, unincorporated Half Moon Bay fringes, San Gregorio, Pescadero, and Año Nuevo. Most new development, land divisions, change of use, and many exterior modifications in the Coastal Zone require a CDP.

Categorical exclusions apply for certain minor improvements, repair/maintenance, and some single-family additions in non-appealable areas. Appealable-area projects (within 300 ft of the mean high tide line, in sensitive habitat, on agricultural land, or in rural areas) can be appealed to the California Coastal Commission after County action. LCP policies require: 100 ft ESHA buffers around riparian, wetland, and sensitive species habitat (reduced to 50 ft on case-by-case basis); public shoreline access easements for most waterfront projects; agricultural protection (preserve Prime Ag Land, ag cluster subdivisions); view protection along scenic coastal corridors; sea-level-rise adaptation and bluff retreat setbacks. Coastal bluff development must include geotechnical and coastal engineering review. Seawalls and shoreline armoring face strict Coastal Act §30235 limits.

Violations & Fines

Unpermitted coastal development: Coastal Act violations $1,000-$15,000 per day plus civil penalties up to $15,000,000 in aggregate, restoration required, possible demolition. Habitat damage: restoration required plus CDFW/USFWS enforcement. Public access obstruction: CCC enforcement under Coastal Act.

Frequently Asked Questions

Do I need a Coastal Development Permit to remodel my kitchen?
Interior remodels and repairs that don't change the building envelope or intensify use are typically categorically excluded from CDP requirements. But additions, exterior changes, and any increase in footprint or height will require at minimum a CDP application, often processed alongside your building permit. Check with Planning at (650) 363-4161.
How do I find out if my property is in the Coastal Zone?
Use the San Mateo County GIS map (smcgov.org/planning/gis-map-zoning-and-other-info-0) and enable the Coastal Zone boundary layer, or check the California Coastal Commission's Coastal Zone Viewer. If your parcel is on the ocean side of Highway 1 or anywhere west of the ridge from Devil's Slide south, assume you are in the Coastal Zone until confirmed otherwise.

Sources & Official References

Other rules in San Mateo County

All San Mateo County rules

California rules heatmap·Compare San Mateo County to another location·View the California environmental rules overview

Get notified when Coastal Development in San Mateo County, CA changes

We'll email you the moment we detect a change in the code. No spam, unsubscribe anytime.

We'll never sell or share your email. One-click unsubscribe in every email.

See something wrong?

Help us keep this page accurate. If you notice an error or outdated information, let us know.

Coastal Development in Cities Across San Mateo County