San Gregorio CA Real Estate & Homes For Sale
San Gregorio is an unincorporated coastal community in San Mateo County, so county planning governs improvements and land use. Buyers should confirm legal access, actual water supply and wastewater arrangements, and coastal permits, and should not assume an agricultural setting or outbuilding allows another use.
Explore San Gregorio, CA real estate and homes for sale with this local guide. Contact Diamond to discuss your criteria and current property-search options.
| County | San Mateo County |
|---|---|
| Local government | Unincorporated — San Mateo County planning |
| Water and sewer | Confirm water supply; private wastewater systems under county health program |
| Housing | Shoreline, inland and sloping rural sites with outbuildings |
| Local rules | Coastal permits; existing use does not establish permission for new uses |
San Gregorio homes: the parcel behind the coastal address
San Gregorio is an unincorporated coastal-area community in San Mateo County. Compare the actual residence and surrounding land rather than assuming the community name identifies one type of property. A countryside home’s usefulness depends on services, access and the documented structures included in the sale.
San Gregorio homes for sale
San Gregorio market report
Separate the existing use from the idea
If your plans involve more than ordinary residential use, write the activity down and ask the relevant agency about the parcel. An agricultural setting or existing outbuilding does not establish permission for a different business, dwelling or visitor use.
Identify legal access, actual water supply and wastewater arrangements. Request system history and agreements where relevant. Evaluate the usable ground and the maintenance route around the residence instead of treating all land area as equally functional.
Buying in San Gregorio
Use the county planning resource for relevant improvement and land-use questions. Where private wastewater systems are present, the county health program provides the official reference for the appropriate review.
The county property workbook helps allocate each material question to an agency, provider, title reviewer or specialist. Compare Pescadero and Half Moon Bay as different property settings and jurisdictions.
Selling a San Gregorio property
Prepare an accurate residence and infrastructure summary. Gather records for substantial work and represented uses, with unresolved items identified. Show the actual access and useful grounds so buyers can understand the property before arranging specialized inspections.
The San Mateo County seller service connects that file with preparation and pricing. Keep future development or operating ideas distinct from the documented features being sold.
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Local property guides
- Buying a Home in San Gregorio: Coastal Permits, Parcel Records and Existing Improvements
- San Gregorio Property Settings Compared: Shoreline, Inland and Sloping Sites
- What Does a San Gregorio Home Cost to Own? Insurance, Maintenance and Utilities
- San Gregorio Home Inspections: Drainage, Foundations, Roofs and Site Access
- Pricing a San Gregorio Home: Views, Access, Condition and Comparable Sales
Explore related property guides
Where San Gregorio is and who governs it
San Gregorio is a small unincorporated community on the south coast of San Mateo County, where State Route 84 from La Honda meets State Route 1. It has no city government. San Mateo County Planning and Building handles zoning, planning permits and building permits, and the Board of Supervisors makes land-use decisions. See our unincorporated San Mateo County guide.
Most San Gregorio parcels are in the County’s Coastal Zone, where the Local Coastal Program (LCP) applies. All development there needs a Coastal Development Permit or an exemption, and projects must also meet County zoning, building and health codes. The LCP steers new development toward existing urban areas and rural service centers and discourages sprawl, so rural coastal land faces more limits than a Midcoast subdivision lot. Ask Planning staff for the parcel’s zoning and LCP land-use designation before you put a price on any plan.
Water, sewer and utilities in San Gregorio
San Gregorio does not appear as its own row in San Mateo LAFCo’s table of districts serving unincorporated areas, and there is no water or sewer district for the community. In practice:
- Wastewater: Homes use onsite (septic) systems regulated by San Mateo County Environmental Health’s land use review and onsite wastewater programs. Environmental Health also reviews planning and building applications that affect a septic system.
- Water: Supply is parcel-specific. It may be a private well, a spring, creek water under a right or a shared system. Environmental Health handles well permits. For a shared system, get the agreement, the maintenance history and the cost-sharing terms.
- Access and power: Many rural parcels are reached by private or shared roads. Ask for recorded easements and any road maintenance agreement. Confirm how electric service reaches the house and outbuildings.
What to ask for in escrow: Get a well flow test and water-quality results, a septic inspection with its permit history, and the permits behind any guest quarters or converted barns. An outbuilding’s current use is not proof that the use is permitted.
Homes, lots and land use in San Gregorio
Property around San Gregorio ranges from homes near the village and beach to larger farm, ranch and hillside parcels, often with barns and other outbuildings. On land like this, zoning and the LCP decide what is possible, along with septic, water and access. A second dwelling, farm stay, event use or business usually needs its own County approval, and some uses may not be allowed at all. Our Coastside land guide and buying land guide go through the checks.
Hazards and insurance to check
- Earthquake fault zones: On November 20, 2025, the California Geological Survey issued a revised official Earthquake Zones of Required Investigation map for the San Gregorio and La Honda quadrangles. It shows Alquist-Priolo fault zones along the San Gregorio Fault Zone. The linked November 2025 map noted no prepared liquefaction/landslide zones for these quadrangles. Check the latest CGS coverage and obtain any required site-specific review; an unmapped area is not proof of no hazard. Look up the parcel in EQ Zapp.
- Tsunami and coastal flooding: For parcels near the beach and the mouth of San Gregorio Creek, check the CGS tsunami hazard area maps and FEMA’s Flood Map Service Center.
- Wildfire: Check the State Fire Marshal’s Fire Hazard Severity Zone viewer. Rural parcels are often in the State Responsibility Area. Get insurance quotes at the start of escrow.
Getting around from San Gregorio
State Route 1 runs north to Half Moon Bay and south to Pescadero. State Route 84 climbs east through La Honda to Woodside and the Peninsula. SamTrans’ fixed Coastside bus routes center on the Midcoast and Half Moon Bay. The rural south coast is served by SamCoast, an on-demand shared-ride service booked by phone, and RediCoast provides ADA paratransit, according to the SamTrans Coastside services page.
Local rules buyers and owners should know
- Coastal Development Permits: Required for most development, including many agricultural structures, unless an exemption applies.
- Fault zone disclosure: If a parcel is inside a mapped Alquist-Priolo zone, the seller must disclose it, and new construction there may need a fault investigation.
- Transfer tax: San Mateo County’s documentary transfer tax is $1.10 per $1,000 of value. San Gregorio is unincorporated, so no city transfer tax applies.
- Property tax: Check the bill for special assessments. See San Mateo County property tax.
Luxury homes and estates in San Gregorio
Around San Gregorio, high-end property usually means a rural coastal estate: ranch or farm acreage, ocean-view hillside parcels and homes with barns or guest quarters. Most of it is in the County’s Coastal Zone, where the Local Coastal Program limits new development on rural land. A Coastal Development Permit, or an exemption, is needed for most work. Parcels along the San Gregorio Fault Zone may also need a fault investigation before new construction.
Due diligence for a high-value purchase: Check EQ Zapp and the November 2025 fault-zone map for the parcel. Get the well flow and water-quality data, the septic permits for every living space, and the County permits for guest units and converted barns. Get the recorded access easements and road agreements. Then check fire hazard and insurance; see our FAIR Plan guide and our guide to insuring a high-value home. For guest-unit questions, see our guest house guide.
Ask Diamond Real Estate Group which permitted private-marketing options fit the property, your goals and the applicable MLS rules. Availability of any particular property is not guaranteed. Related: San Mateo County luxury homes.
San Gregorio real estate: questions people ask
Is San Gregorio in the Coastal Zone?
Most San Gregorio parcels are. In the Coastal Zone, San Mateo County’s Local Coastal Program requires a Coastal Development Permit or an exemption for development, and County zoning, building and health rules also apply. Confirm a parcel’s status and land-use designation with County Planning before you rely on a building plan.
How do San Gregorio homes get water and sewer?
Confirm service for the actual parcel rather than inferring it from the community name. For onsite systems, Septic systems and wells are permitted by San Mateo County Environmental Health. Water may come from a well, a spring or a shared system, so ask for flow tests, water-quality results and any shared-system agreements.
Is San Gregorio near an earthquake fault?
Yes. The state’s November 2025 revised map for the San Gregorio and La Honda quadrangles shows Alquist-Priolo zones along the San Gregorio Fault Zone. Look up the parcel in EQ Zapp. A parcel inside a zone must be disclosed, and new construction may need a fault investigation.
Can I run a farm stay or events on a San Gregorio property?
Only if County zoning and the LCP allow that use on the parcel and you get the required permits. Some uses may not be allowed at all. Existing barns or past activity do not establish permission. Ask County Planning before you buy, and budget time for coastal permit review.
Sources for this section
- San Mateo County Planning and Building, Planning Permits: https://www.smcgov.org/planning/planning-permits
- San Mateo County Planning, Local Coastal Program: https://www.smcgov.org/planning/local-coastal-program
- San Mateo LAFCo, Special Districts Serving Unincorporated Areas: https://www.smcgov.org/lafco/special-districts-serving-unincorporated-areas
- San Mateo County Health, Land Use Review and Onsite Wastewater (Septic) Programs: https://smchealth.org/services/smch-services/water-protection-land-use-onsite-systems/land-use-review-and-onsite-wastewater-septic-programs/
- California Geological Survey, EZRIM San Gregorio and La Honda quadrangles (Nov. 20, 2025): https://www.conservation.ca.gov/cgs/Documents/Publications/EZRIM/SAN_GREGORIO_LA_HONDA_EZRIM_a11y.pdf ; EQ Zapp: https://www.conservation.ca.gov/cgs/geohazards/eq-zapp
- California Geological Survey, Tsunami Hazard Area Maps: https://www.conservation.ca.gov/cgs/tsunami/maps
- FEMA Flood Map Service Center: https://msc.fema.gov/portal/home
- Office of the State Fire Marshal, Fire Hazard Severity Zones: https://osfm.fire.ca.gov/what-we-do/community-wildfire-preparedness-and-mitigation/fire-hazard-severity-zones
- SamTrans, Coastside Services: https://www.samtrans.com/service-info/coastside-services
- San Mateo County Assessor-County Clerk-Recorder, Documentary Transfer Tax: https://smcacre.gov/county-clerk-recorder/documentary-transfer-tax
What is your property in San Gregorio worth?
Planning a sale or weighing your next move? Request a broker market analysis based on the property, relevant comparable sales and the local setting.
