Brentwood ADUs: How to Add an Accessory Dwelling Unit to Your Home

The idea of adding more space and value to a Brentwood property without sacrificing privacy or aesthetics has never been more appealing. As housing needs evolve and investment opportunities shift, Accessory Dwelling Units (ADUs) offer Brentwood homeowners a flexible, future-focused solution. Whether you're considering space for extended family, a private office, or long-term rental income, building an ADU in Brentwood can transform how your home works for you.

Brentwood’s wide lots, mature landscaping, and privacy-focused architecture make it an ideal neighborhood for adding an ADU. Whether detached in a backyard, converted from an existing garage, or attached to the main house, these secondary units offer residents a chance to accommodate extended family, create rental income, or plan for future needs.

Thanks to recent changes in California law, the permitting process has become more streamlined, and in a high-demand neighborhood like Brentwood, the return on investment is often significant. Homeowners considering ADUs are well-positioned to take advantage of these opportunities, but it's important to follow the proper steps to avoid delays or compliance issues.

An ADU is a self-contained residential structure located on the same lot as a single-family or multi-family home. In Brentwood, ADUs can take several forms:

• Detached ADUs: A separate structure in the backyard or rear portion of the lot
• Attached ADUs: An expansion or addition to the main home
• Garage Conversions: Turning a legally permitted garage into a livable unit
• Junior ADUs (JADUs): A smaller unit (up to 500 sq. ft.) created within the primary home with a separate entrance

To be legally recognized, the unit must have its own entrance, a full kitchen and bathroom, and meet city building and safety codes.

Brentwood falls under the jurisdiction of the City of Los Angeles, which has specific ADU regulations in place under LAMC Section 12.22.A.33. In order to be compliant, homeowners must follow local development standards for height, size, and placement.

In most single-family zones, you can build a detached ADU up to 1,200 square feet, provided it meets the four-foot side and rear setback rule. If the ADU is located above a garage or within a hillside area, additional review may be required.

Lot coverage, distance from the main residence, and neighborhood overlays (such as the Brentwood-Pacific Palisades Community Plan) can influence design approvals. A local architect or contractor familiar with ADUs in Brentwood can help you navigate these details to avoid unnecessary back-and-forth with the city.

Before you can break ground, you’ll need permits from the Los Angeles Department of Building and Safety (LADBS). This process generally includes:

• Site plan and architectural drawings
• Structural engineering documents (if required)
• Plan check submission and review
• Building, electrical, and plumbing permits

Permitting timelines can vary depending on whether the ADU is new construction or a conversion. While the state of California mandates that cities approve ADU plans within 60 days, the timeline may stretch longer if corrections or revisions are requested.

For many Brentwood homeowners, hiring a permit expeditor or working with a design-build firm can help move the process forward more efficiently.

All ADUs must have access to utilities—water, gas, electricity, and sewer. In Brentwood, this usually means connecting to the main house’s systems or installing separate meters, depending on your intended use and city requirements.

Fortunately, no additional off-street parking is required if the ADU is located within half a mile of public transit (including bus stops), which applies to much of Brentwood. However, if you're converting a garage, you’ll need to show that the lost parking doesn’t violate existing parking codes or provide replacement spaces elsewhere on the lot.

These logistical details are often overlooked at the start but can impact your timeline and budget later, so it's wise to confirm them early.

While ADUs are subject to city regulations, design still matters—especially in a neighborhood like Brentwood, where aesthetics and property value are closely tied. Many homeowners opt for architecture that mirrors or complements the main house, using materials and finishes that align with the neighborhood's style.

High-end finishes, thoughtful landscaping, and separate walkways or entrances can make the unit feel private and independent, which is especially appealing for renters or extended family. In Brentwood, subtle elegance tends to go further than flashy design, and attention to detail can make your ADU feel like a true extension of your home rather than an afterthought.

Recent California laws have made it easier to build ADUs, but local use restrictions still apply. In Brentwood, you can use your ADU for:

• Long-term rental income (30 days or longer)
• Family or caregiver housing
• Guest accommodations

Short-term rentals (under 30 days) are not permitted in ADUs. If you're considering renting out the unit, make sure you understand the local guidelines and required rental permits, especially as the city continues to adjust its housing policies.

For homeowners in Brentwood, adding an ADU is about more than just square footage; it’s a strategic investment in flexibility, function, and future value. Whether you're planning for aging parents, rental income, or creating space for a growing household, a well-built ADU can elevate how your property serves you over time.

With strong property values, generous lot sizes, and updated state laws supporting ADU development, Brentwood remains one of the most ADU-friendly and opportunity-rich neighborhoods in Los Angeles.

If you’re considering adding an ADU to your Brentwood home, having the right guidance from the start can save time, money, and frustration. From zoning reviews to contractor referrals and design insights, working with an experienced real estate advisor helps you move forward with confidence.

To learn more about ADUs in Brentwood and how they can enhance your property, reach out to Mary Lu Tuthill. With deep local expertise and a thoughtful approach to home value, Mary Lu can help you navigate the process and make the most of your investment.