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

What multifamily in Brentwood looks like

Brentwood is mostly single-family subdivisions, so its multifamily stock is smaller and more spread out than in older East Bay cities. Investors will find duplexes and triplexes in the older blocks around downtown, small apartment buildings and townhome projects in the R-2 and R-3 zones, apartment communities inside planned development (PD) districts, and a growing number of ADUs behind single-family homes. A two-to-four-unit purchase here often means a house plus an ADU or a small infill project, not a large walk-up building. See financing 2-4 unit properties and apartment building loans.

Where the zoning allows it

Brentwood’s multifamily rules are in Title 17 of the municipal code. Many apartment sites are in numbered PD zones (PD-1 to PD-72), whose own chapters set the density, so read the PD chapter for any site that is not R-2 or R-3.

Both R-2 and R-3 require design and site development review for every housing project, which adds time even when the use is permitted.

SB 9 in Brentwood. Chapter 17.797 allows two primary units per single-family parcel, plus one ADU or junior ADU per primary unit, for up to four units. After an urban lot split, each new parcel is limited to two units of any kind. Side and rear setbacks are four feet. Parking is one space per unit, or none within half a mile of qualifying transit. Two points matter to investors. The owner must live in one of the units as a principal residence. The owner must also record a covenant barring rentals under 30 days. Sites with rent-restricted or recently tenant-occupied housing are excluded. See our SB 9 lot split guide.

ADUs. Brentwood regulates ADUs and junior ADUs under Chapter 17.715, and both R-2 and R-3 list ADUs as permitted uses. See our ADU investment guide. We did not open the city’s ADU chapter, so confirm size and parking standards with the city.

Rent rules: state law only

Brentwood is not on the Attorney General’s list of Contra Costa cities with local rent caps. That list names only Antioch, Concord and Richmond. Covered Brentwood units therefore follow the statewide Tenant Protection Act. Contra Costa sits in the AG’s San Francisco Area region, where the cap is 6.3% for increases starting August 1, 2025 and 8.8% for increases from August 1, 2026 through July 31, 2027. Many Brentwood rentals are newer homes and condos, and AB 1482 exempts housing built within the last 15 years and certain single-family homes and condos when the right notice is given. Check each unit’s status. Just cause and relocation rules come from state law. See our AB 1482 guide and just cause eviction guide.

Brentwood rental property rules

Rental inspections. Under Chapter 8.44, the city inspects the exterior of every rental property at least once every two years. A rental is any dwelling occupied by someone other than the owner of record on the assessment roll. Deficiencies get a written notice and reinspection until corrected, and the city may inspect more often. Mobile home park units, hotels and motels, and government-exempt housing are excluded. Ask the seller for past inspection notices and proof that any deficiency was cleared.

No short-term rentals. Chapter 17.796 makes it unlawful to rent any dwelling, or part of one, for 30 consecutive days or less. The ban also covers renting amenities such as a pool or backyard. It expressly reaches SB 9 units. Underwrite Brentwood units on monthly or longer leases only.

Condo conversions. Converting apartments to condominiums is regulated under Chapter 17.740. Read it before pricing a building on a conversion exit.

Newer buildings, balconies and utilities

Much of Brentwood’s apartment stock dates from the 1990s onward, so the soft-story concerns of older Bay Area cities apply less often. Wood-frame buildings of three or more units with elevated balconies, decks or walkways still need SB 721 inspections. For the few older downtown buildings, ask an engineer about seismic retrofit. Brentwood runs its own sewer and water rules under Titles 13 and 14 of the municipal code. New units trigger development impact fees under Chapter 16.130, so get a fee estimate early for any ADU or infill plan.

Underwriting a Brentwood multifamily purchase

1. Confirm the zone: R-2, R-3, a PD chapter, or a specific plan, and calculate the allowed density.
2. Classify each unit under AB 1482, including the new-construction and single-family exemptions, and model increases at the 8.8% statewide cap.
3. Remove any short-term rental income from the seller’s numbers.
4. Request Chapter 8.44 inspection history and open deficiency notices.
5. Collect leases, the rent roll and two years of statements, and get estoppel certificates.
6. Add reassessed property tax, any Mello-Roos or assessment levy, the county transfer tax of $0.55 per $500 (Clerk-Recorder) and impact fees for added units in our rental property analysis.

Questions people ask

Sources & notes

1. California Attorney General, Rent Caps
2. Brentwood Municipal Code, Title 17 Zoning (GoCodebook): Chapters 17.140, 17.150, 17.320, 17.796, 17.797
3. Brentwood Municipal Code, Chapter 8.44 Rental Property Inspection
4. Contra Costa Clerk-Recorder, Documentary Transfer Tax

Note: The ADU (17.715), condominium conversion (17.740) and impact fee (16.130) chapters were identified in the code index but not read in full. Inspection fees and any registration step are set by administrative procedure and were not verified.

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

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