Multifamily and Duplex Properties for Sale in San Gregorio: Zoning and Rent Rules

What multifamily in San Gregorio looks like

San Gregorio has no apartment district. Its rental housing is a small number of homes in and near the village, ranch houses with second dwellings, farm labor housing on agricultural land, and cottages rented to people who work on the South Coast. "Multifamily" here usually means two or three units on one rural parcel, a legal second unit, or employee housing tied to a farm or business. Every one of those depends on County zoning, the Coastal Zone permit system and, above all, whether the well and septic system can support another household. For two to four units, see financing 2-4 unit properties; apartment building loans rarely apply in a place this small.

Where the zoning allows it

San Gregorio is unincorporated, so County Title 8 and the Local Coastal Program control. The LCP policies designate San Gregorio and Pescadero as the South Coast’s two Rural Service Centers, where Policy 1.12 calls for infill to meet housing needs created by local jobs. The 1980 buildout estimate in the LCP put San Gregorio at about 40 homes.

The permit cap. LCP Table 1.4 allows the San Gregorio watershed four building permits a year for new rural residential construction. Policy 1.24(a) exempts affordable and farm labor housing from that limit, and Policy 1.8(c)(1) exempts both from density credit requirements, which makes them the most realistic way to add several units on one ranch.

ADUs. Chapter 8.396, adopted in 2020 and replaced by Ordinance 4851 in 2021, lists the Coastal Zone R-1, R-2 and R-3 districts as the ones where ADUs are allowed. It does not mention PAD, so an ADU on agricultural land may need to qualify as a farm labor or second dwelling under PAD instead; ask Planning. Where the chapter applies, one detached ADU can pair with one JADU, and a JADU needs an owner-occupancy deed restriction. See our ADU investment guide.

SB 9. In unincorporated areas, SB 9 lot splits and two-unit projects generally apply only within a Census urbanized area or urban cluster, and not on most farm or resource land. San Gregorio is unlikely to qualify; confirm with the County. See our SB 9 lot split guide.

Rent rules: state law only

The Attorney General’s rent cap page, updated July 16, 2026, places San Mateo County in the San Francisco Area, with covered units allowed up to 8.8% for increases from August 1, 2026 through July 31, 2027, and names East Palo Alto as the county’s only city with local rent stabilization. Unincorporated San Gregorio has no local rent ordinance for houses or apartments, so AB 1482’s cap and just-cause rules apply to covered units. Many rural rentals are single-family homes owned by individuals, which can be exempt with the proper notice. See our AB 1482 guide and just cause eviction guide.

The County separately regulates space rents in unincorporated mobile home parks, limiting increases to once a year; see our San Mateo County multifamily guide.

San Gregorio rental property rules

• ADUs are long-term only. Section 8.396.050 requires ADU rentals to run longer than 30 days.
• Short-term rentals. Homes in the Coastal Zone need a County short-term rental permit under Chapter 8.368, valid three years, with a 180-night annual cap and occupancy of two people per bedroom plus two. Owners also register for transient occupancy tax.
• Farm labor housing. PAD allows it by Planned Agricultural Permit on both prime and non-prime land; confirm any occupancy limits tied to the farm operation.
• Transfer tax. Only the County’s documentary transfer tax applies, at $0.55 per $500 of value.

Wells, septic and coastal permits

Water is the usual limit on adding units. In PAD, each new non-agricultural parcel must show a safe, adequate well on the parcel, one well may serve no more than four new parcels, and farm and habitat water may not be reduced. The code figures 315 gallons a day per home in the two driest months when matching homes to density credits. New parcels must also include an on-site sewage disposal area, and the LCP requires septic systems to protect ground and surface water. Plan on a well yield test, a water quality test and a septic evaluation by County Environmental Health before counting any added unit. Nearly any new unit also needs a Coastal Development Permit. Older ranch buildings may need a seismic retrofit review, and any building of three or more units with elevated balconies needs SB 721 balcony inspections.

Underwriting a San Gregorio multifamily purchase

1. Confirm each unit’s legal status and permit history; unpermitted ranch units are common on rural land.
2. Test well yield and quality, and have the septic system evaluated for every existing household.
3. Check zoning, LCP designation and density credits before planning additions.
4. Classify units under AB 1482 and model increases at or below 8.8% for covered units.
5. Collect leases and estoppel certificates, especially for farm employee housing.
6. Rebuild expenses with reassessed taxes, well and septic maintenance and insurance in our rental property analysis.

Questions people ask

Sources & notes

1. San Mateo County Local Coastal Program page
2. Local Coastal Program Policies (2021 edition)
3. Title 8, Chapter 8.106 PAD (GoCodebook)
4. Title 8, Chapter 8.396 ADUs, Coastal Zone
5. Title 8, Chapter 8.368 Short-Term Rentals, Coastal Zone
6. San Mateo County, transient occupancy tax
7. San Mateo County Clerk-Recorder, documentary transfer tax
8. California Attorney General, rent caps

Note: We did not confirm the zoning of individual village parcels, read the LCP Land Use Plan Map, or verify SB 9’s application to San Gregorio; the SB 9 statement summarizes state law and was not checked against a specific parcel. The mobile home rent note comes from our county page.

General information, not legal or tax advice. Last reviewed October 2026 by Matthew Martinez.

Related: San Gregorio real estate guide · Commercial real estate in San Gregorio · Multifamily investing guide · Investor services