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

What multifamily in Alamo looks like

Alamo is overwhelmingly a community of single-family homes on large lots, and its rental market reflects that. Multifamily options are limited to:

• A small number of apartment and condominium buildings and townhomes near the Danville Boulevard commercial core
• Senior housing communities
• Single-family homes with ADUs or JADUs, which are the most common way to add rental units
• Duplexes on the few lots zoned for two units

Because supply is small, most investor activity here involves adding ADUs or buying the occasional small building near the core. For financing, see financing 2-4 unit properties and apartment building loans.

Where the zoning allows it

Contra Costa County zones Alamo under Division 84. The county’s 2045 General Plan steers where new multifamily can go.

What the General Plan says. The Stronger Communities Element of the 2045 General Plan, adopted November 5, 2024, sets the Alamo vision:

• Guiding Principle 3 locates multifamily homes within one mile of the commercial core.
• The land use vision keeps existing neighborhoods as they are and allows higher-density housing in the Danville Boulevard mixed-use area.
• Policy 2 supports a mix of housing types, including options for downsizing, while keeping the single-family character.
• Policy 9 discourages roofs over 40 feet.

In other words, any apartment opportunity in Alamo is near the core.

Housing element. The county’s housing element update, filed on CEQAnet in December 2022, planned for a 7,610-unit regional housing need across the unincorporated county, on about 560 acres inside the urban limit line. Alamo appears in the project’s location list. Ask the county whether a parcel is on the HE-C inventory, because that changes what can be built.

ADUs. Chapter 82-24 allows these on a single-family lot:

• one conversion ADU and one JADU inside the house
• one detached ADU of up to 1,000 square feet, or 1,200 on lots of 12,000 square feet or more, which covers many Alamo lots

An existing apartment property can convert non-livable space into ADUs for up to 25% of its units. It can also add detached ADUs, up to eight or the number of existing units, whichever is less. ADUs cannot be rented for less than 30 days. Lots on septic need health officer approval first. See our ADU investment guide.

SB 9. State SB 9 law applies to eligible single-family lots, though high fire hazard areas in the Alamo hills may be excluded. We did not find a county SB 9 chapter in the zoning title. See our SB 9 lot split guide.

Inclusionary housing. Under Chapter 822-4, new projects of five or more units must make 15% of units affordable. In rentals, at least a fifth of those go to very low income households, for 55 years. Projects of 5 to 125 units can pay an in-lieu fee instead. One- to four-unit projects are exempt.

Rent rules: state law only

Unincorporated Contra Costa County has no local rent cap. The Attorney General’s chart lists Antioch, Concord and Richmond as the county’s only local programs. Covered Alamo units follow the statewide cap for the San Francisco Area region: 6.3% for increases from August 1, 2025, and 8.8% from August 1, 2026 through July 31, 2027. State just cause rules apply to covered tenancies. Many Alamo rentals are single-family homes owned by individuals, which can be exempt from the state cap and just cause rules if the lease includes the required notice. See our AB 1482 guide and just cause eviction guide.

Alamo rental property rules

We did not find a county rental registry, rent review program or local just cause ordinance that applies in Alamo. The practical rules come from elsewhere:

• Planned unit conditions. Condominium and townhome projects built under P-1 approvals may carry conditions or HOA rules that limit rentals. Check the final development plan and CC&Rs.
• Short stays. ADUs cannot be rented for less than 30 days.
• Code enforcement. The county’s Department of Conservation and Development handles code complaints in Alamo, according to the county’s Alamo page. Ask whether a property has open cases.
• Community review. The Alamo Municipal Advisory Council reviews many land use applications, including subdivisions and P-1 deviations.

Building, fire and closing-cost issues

Wooded hillsides surround much of Alamo, and the general plan lists wildfire protection as a guiding principle. Insurance cost and availability belong in underwriting for any hillside rental. Older apartment buildings near the core warrant a seismic retrofit review. Buildings of three or more units with elevated balconies need SB 721 inspections. There is no city transfer tax, only the county’s $0.55 per $500.

Underwriting an Alamo multifamily purchase

1. Confirm the zoning and any P-1 development plan, and whether the parcel is on the housing element inventory.
2. Check the lot size against the ADU size tiers, and whether the lot is sewered or on septic.
3. Classify each unit under the state Tenant Protection Act, including the single-family exemption notice.
4. Review HOA rules and development plan conditions for rental limits.
5. Collect leases, the rent roll and two years of statements, and get estoppel certificates.
6. Add wildfire insurance and reassessed property tax to your rental property analysis.

Questions people ask

Sources & notes

1. Contra Costa County 2045 General Plan and Stronger Communities Element
2. County Ordinance Code Division 84: D-1, M-29, R-B and HE-C (GoCodebook)
3. Chapter 82-24, ADUs and Chapter 822-4, Inclusionary Housing
4. CEQAnet, Contra Costa County Housing Element Update NOP
5. Contra Costa County, Alamo
6. California Attorney General, Rent Caps
7. Contra Costa Clerk-Recorder, Documentary Transfer Tax

Note: We did not identify which Alamo parcels, if any, are on the HE-C inventory. The HE-C chapter’s ordinance citations are inconsistent in the online code, so confirm with the county.

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

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