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

What multifamily in San Anselmo looks like

Most of San Anselmo’s rental housing is small. It includes duplexes and triplexes on the flat streets near downtown, older courtyard apartments, and apartments above San Anselmo Avenue shops. Larger complexes are rare, so a "multifamily" purchase here usually means two to eight units. Many buildings predate modern codes and sit close to the creek or on hillsides. For financing, see financing 2-4 unit properties and apartment building loans.

Where the zoning allows it

San Anselmo’s Table 3A does not have a separate two-family category. It sorts housing into multifamily of two to four units and of five or more. Densities come from Table 4A.

Heights in the residential districts run 30 feet on slopes under 25% and 35 feet on steeper lots. A 15,000-square-foot R-3 lot could support about ten units at 30 per acre before any density bonus. The same lot in R-2 would support about four. R-3 lots also need 75 feet of average width and 50 feet of street frontage, which rules out many narrow older parcels, so measure before assuming the full count. In C-1, housing projects of 8 to 10 units off historic sites may use 1.25 FAR. Listed Housing Element sites allow projects with 20% lower-income units by right.

ADUs and SB 9. The town has its own ADU chapter and an urban lot split and two-unit chapter for the single-family zones. Table 3A requires two permits for these units, one for the use and one under the state SB 9 statutes. See our ADU investment guide and SB 9 lot split guide.

Rent rules: state law only

We found no rent stabilization, just cause or rent mediation chapter in San Anselmo’s code index. The tenant-related chapter we found is Chapter 14, which bars discrimination based on source of income. Marin County’s just cause and mediation ordinances apply only in unincorporated areas, such as nearby Sleepy Hollow, not inside the town. Confirm with the town that no newer ordinance is pending.

Rent caps. AB 1482 applies to covered units. The Attorney General’s rent cap page sets the San Francisco Area maximum at 8.8% for increases from August 1, 2026 through July 31, 2027. See our AB 1482 guide.

Just cause. State just cause rules apply after 12 months of tenancy for covered units. No-fault terminations require relocation assistance equal to one month’s rent. See our just cause eviction guide.

San Anselmo rental property rules

• Source of income. Under Chapter 14, landlords may not refuse tenants or treat them differently because of housing vouchers or other lawful income.
• SRO housing. The town regulates single-room occupancy buildings under Article 19 of the zoning chapter.
• Demolition. Removing an existing building requires a demolition permit under Article 21, which matters for a teardown-and-rebuild plan.
• Transfer tax. The town’s Title 8, Chapter 4 sets $0.275 per $500, excluding liens, administered by the County Recorder. The county charges $0.55 per $500, per the Recorder’s sheet. That sheet lists only San Rafael with an added city tax, so confirm the split with escrow.

Sewer laterals, flood zones and older buildings

The Ross Valley Sanitary District requires a lateral Certificate of Compliance when a property is sold, when a remodel tops $75,000 and when a bathroom is added. In condo or common-interest buildings, each owner is responsible for the lateral segment they maintain. The process includes a video inspection, a sewer permit and a pressure test witnessed by the district. On a fourplex with an old clay lateral, replacement can be a meaningful closing cost, so line it up early. Downtown parcels near San Anselmo Creek may be in a FEMA flood zone, where foundation work follows the town’s flood rules. Older wood-frame buildings deserve a seismic retrofit review. Buildings with three or more units and elevated decks or stairs need SB 721 inspections.

Underwriting a San Anselmo multifamily purchase

1. Confirm the zone and calculate legal unit count from the units-per-acre limit in Table 4A.
2. Check permits for every unit. Older buildings often have added units that were never legalized.
3. Classify each unit under AB 1482 and model increases at or below 8.8%.
4. Order the sewer lateral video inspection at the start of escrow and price any repair.
5. Check flood zone status and insurance for creekside parcels.
6. Collect leases, the rent roll and estoppel certificates, then rebuild expenses with reassessed taxes in our rental property analysis.

Questions people ask

Sources & notes

1. San Anselmo Municipal Code, Title 10 Chapter 3 Article 3 (Table 3A) and Article 4 (Table 4A) (GoCodebook, October 2026)
2. Title 10 Chapter 4, Urban Lot Splits and Two-Unit Development and Chapter 6, ADUs (titles reviewed)
3. Title 10 Chapter 14, Income-Based Rental Housing Discrimination (title reviewed)
4. Title 8 Chapter 4, Real Property Transfer Taxes
5. Ross Valley Sanitary District, lateral compliance
6. California Attorney General, Rent Caps and Marin County Recorder, transfer tax

Note: Some Table 3A notes, such as note 18, were cut off in the copy we read. We did not read the text of the SB 9, ADU or Chapter 14 chapters, or any short-term rental rules.

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

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