Multifamily and Duplex Properties for Sale in Lagunitas: Zoning and Rent Rules

What multifamily in Lagunitas looks like

In Lagunitas, "multifamily" usually means a house with a permitted ADU or junior ADU, an older duplex or cottage pair, upstairs units over a commercial building, or one of the few small apartment buildings in the village. The San Geronimo Valley Community Plan, adopted in December 1997, notes that apartments and multifamily units exist in Woodacre, Forest Knolls and Lagunitas. It also says many valley second units were built without permits and should be treated as a housing resource. For buyers, the limits are septic capacity, creek setbacks and whether each unit is legal. For financing, see financing 2-4 unit properties and apartment building loans.

Where the zoning allows it

Lagunitas follows Marin County’s Chapter 22.10 residential districts and the valley’s SGV combining standards. The single-family districts do not list two-family or multifamily dwellings.

Housing Element sites. The county’s West Marin sites list assigns 46 units to Lagunitas: 32 lower-income, 10 moderate and 4 above moderate. They are the office properties at 7120 Sir Francis Drake (16) and 7282 Sir Francis Drake (14), and Saint Cecilia Church (16). Table 2-12 sets each at 20 units per acre in Form Based Code T3 and T4 zones, with the office sites limited to 1.5 acres. Projects meeting the code are approved ministerially, but they still need a workable wastewater solution.

ADUs and SB 9. ADUs and JADUs are permitted in all county residential districts. See our ADU investment guide. SB 9 applies only in urbanized areas and urban clusters; many Lagunitas parcels may not qualify, and septic and creek rules would limit them anyway. Confirm with county planning and see our SB 9 lot split guide.

Rent rules: state law plus county ordinances

Rent cap. No local cap applies. The Attorney General’s rent cap page sets the AB 1482 maximum for the San Francisco area, which includes Marin, at 8.8% for increases from August 1, 2026 through July 31, 2027. Many Lagunitas rentals are single-family homes or owner-occupied duplexes that may be exempt; see our AB 1482 guide.

County just cause. Marin’s Chapter 5.100, Ordinance 3705 of December 2018, applies to properties with three or more units on one legal lot. Permitted ADUs and JADUs do not count toward three, but unpermitted units do. That matters in Lagunitas, where older unpermitted cottages are common. A valid termination also requires a business license, rental registry entry, tenant rights notice and a copy of the notice sent to the CDA within 10 days. See our just cause eviction guide.

Mediation. Under the county’s mandatory mediation program, increases above 5% in 12 months go to mediation if the tenant asks within 10 calendar days.

Source of income. The county’s Renting in Marin page states that landlords may not refuse tenants because they use vouchers.

Lagunitas rental property rules

• Business license. Every rental needs a county business license, $15 per dwelling unit per year.
• Health permit. Properties with three or more non-owner-occupied units generally need a county Environmental Health permit and are subject to multi-unit inspections.
• Short-term rentals. Lagunitas is its own STR township. The county’s administrative procedures set 6 initial licenses dropping to 4. ADUs created after January 1, 2020 under the state exemption cannot be licensed. Plan on long-term tenancies.

Septic, creeks and water

Septic is the real density limit. There is no sewer in Lagunitas. The community plan says a leach field needs roughly an acre, some lots lack the soil or space for one, and the valley floor’s high winter water table can cause failures. Adding a unit usually means proving septic capacity. Ask for the septic permit and records from county Environmental Health before you count on an ADU.

Stream Conservation Areas. The county’s 2024 SCA rules, effective August 18, rezoned every valley lot into a combining district, set a 35-foot no-touch zone along streams and capped residential additions in the SCA at a 300-square-foot footprint. The ordinance covers 1,485 valley households and is aimed at protecting Lagunitas Creek’s endangered coho. A creekside duplex may have little room to expand.

Water. Marin Water serves the valley from its reservoirs, per the community plan. Confirm meter size and any added-unit charges.

Older buildings. Many Lagunitas homes and cottages are older wood-frame buildings on slopes or near creeks. Consider a seismic retrofit check, and for three or more units with elevated decks, SB 721 inspections.

Underwriting a Lagunitas multifamily purchase

1. Confirm the zoning and whether each unit is permitted; unpermitted units affect both legality and just cause coverage.
2. Get septic permits, capacity and inspection history.
3. Map creeks and the SCA combining district against existing and planned structures.
4. Classify tenancies under AB 1482 and the county just cause rule.
5. Verify the business license, registry entries and tenant rights notices, and collect estoppel certificates.
6. Model septic repair reserves, insurance and taxes in our rental property analysis.

Questions people ask

Sources & notes

1. San Geronimo Valley Community Plan, adopted Dec. 2, 1997 (historical society copy)
2. Marin County Code (GoCodebook): Ch. 22.10, Ch. 22.12, Ch. 22.14 incl. Table 2-12
3. Marin County, West Marin housing element sites
4. Marin County, San Geronimo Valley SCA policies
5. Marin County renter pages: Renting in Marin, Just Cause, Mandatory Mediation
6. Marin County: STR administrative procedures, business license, multi-unit inspection
7. California Attorney General, Rent Caps

Note: We did not open the zoning map, SCA ordinance text or county SB 9 eligibility mapping.

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

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