Multifamily and Duplex Properties for Sale in Moss Beach: Zoning and Rent Rules

What multifamily in Moss Beach looks like

Moss Beach income property is mostly small-scale: single-family homes with a permitted second unit, a few duplexes and cottage pairs, and occasional units above commercial space near Highway 1. Large apartment complexes are not part of the picture. The community is unincorporated, so San Mateo County zoning and the Local Coastal Program apply, and the Montara Water and Sanitary District serves water and sewer. For two to four units, see financing 2-4 unit properties; for five or more, apartment building loans.

Two local factors matter more here than anywhere else on the coast: the Seal Cove landslide area and the noise and avigation rules for homes north of Half Moon Bay Airport.

Where the zoning allows it

Title 8 Chapter 8.08 lists the County’s districts. Use the County map to confirm a parcel’s zoning; we did not verify the zoning on specific Moss Beach streets.

Floor area. S-17 allows floor area of 0.53 times the lot on lots of 5,000 to 11,698 square feet, 0.48 on smaller or narrower lots, and a 6,200-square-foot ceiling above that. Garages and large covered porches count.

ADUs. The County allows ADUs in all Coastal Zone residential districts under Chapter 8.396, per its ADU page. The LCP page links Map 3.1, a special ADU parking map for Moss Beach and Montara, which can change what parking an ADU must provide. See our ADU investment guide.

SB 9. A qualifying single-family lot may support a second unit or split under state law, subject to Coastal Act review and the cap below. See our SB 9 lot split guide.

Rent rules: state law only

The Attorney General’s rent cap page, updated July 16, 2026, puts San Mateo County in the San Francisco area: increases on covered units from August 1, 2026 through July 31, 2027 may reach 8.8%. Moss Beach has no local apartment rent ordinance. The County’s own rent limits apply to mobile home spaces in unincorporated parks, not to houses or apartments. Use our AB 1482 guide and just cause eviction guide.

Moss Beach rental property rules

Midcoast cap. Policy 1.23 of the LCP policies limits the urban Midcoast, which includes Moss Beach under Policy 1.4, to 40 new units a year, second units included. On its cap and waitlist page, updated October 27, 2026, the County says 102 units were permitted in 2025, so just 18 remain for 2026 and 2027. It will not accept new residential building permit applications until January 1, 2028 or until an LCP amendment providing relief is approved. Approved projects wait in line by approval date, and ADU owners can hold a place by filing a Formal CDX.

The pending amendment. A Coastal Commission hearing on amendment LCP-2-SMC-26-0048-1, which would recalculate the cap, is set for November 4, 2026. We did not know the result at review, and the Commission can extend its deadline.

Short-term rentals. A Coastal Zone short-term rental permit is required for stays under 30 days. Permits are limited to legal residences on R-1 or R-3 parcels, 180 nights a year, and occupancy of two per bedroom plus two. ADUs are excluded, and a local contact must live within 20 miles.

Transfer tax. The County’s documentary transfer tax is 55 cents per $500; no city tax applies.

Seal Cove, the airport and utility issues

Seal Cove. The County’s Seal Cove page reports accelerating landslide movement. San Lucas Avenue at Ocean Boulevard has been closed since March 2023 and Del Mar Avenue since January 2025. Cracks on La Grande Avenue west of San Ramon Avenue are under watch, and some homes may be yellow- or red-tagged after inspection, which restricts their use. An updated geologic study went out for public review on December 15, 2025 to inform future LCP policies. A rental in this area needs a geotechnical opinion, and an insurer and lender check, before an offer firms up.

Airport. Under S-17, new dwellings north of Half Moon Bay Airport need an acoustical analysis and an avigation easement recorded to the County. Ask whether existing units were built under those conditions.

Water and sewer. The Montara Water and Sanitary District serves about 1,658 active water connections from nine wells and treatment plants, and pumps sewage through an intertie to a plant in Half Moon Bay. The district lifted its old connection moratorium after 2013. Ask for the parcel’s connection history and any recent line repairs, especially near Seal Cove.

Older buildings. Wood-frame coastal homes deserve a seismic retrofit review, and buildings of three or more units with elevated balconies need SB 721 inspections.

Underwriting a Moss Beach multifamily purchase

1. Confirm the zoning and S district, and map the parcel against the Seal Cove area.
2. Verify every unit’s permits; legalizing an unpermitted unit now waits on the cap.
3. Classify units under AB 1482 and hold modeled increases at or below 8.8% for covered units.
4. Leave new ADU or SB 9 income out of the base case until a permit can issue.
5. Collect leases, MWSD records and estoppel certificates.
6. Rebuild expenses with reassessed taxes, geotechnical monitoring and coastal insurance in our rental property analysis.

Questions people ask

Sources & notes

1. Title 8, Chapter 8.08 districts and Chapter 8.154 S-17 Midcoast (GoCodebook)
2. Chapter 8.28 R-3, Chapter 8.68 C-1, Chapter 8.106 PAD
3. San Mateo County LCP policies and LCP page
4. San Mateo County, urban Midcoast building permit cap and waitlist
5. San Mateo County, Seal Cove information
6. San Mateo County, ADUs
7. San Mateo County, short-term rental permit (Coastal Zone)
8. Montara Water and Sanitary District, FAQ
9. California Attorney General, rent caps
10. San Mateo County ACRE, documentary transfer tax

Note: Parcel zoning, Seal Cove boundaries and the November 4, 2026 Coastal Commission outcome were not confirmed.

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

Related: Moss Beach real estate guide · Commercial real estate in Moss Beach · Multifamily investing guide · Investor services