ADU Regulations at a Glance
Westchester ADU Rules & Regulations
California State ADU Laws
California has some of the most progressive ADU legislation in the country. Recent laws including AB 68, SB 13, AB 881, AB 2221, and SB 897 have significantly streamlined the ADU approval process and reduced barriers for homeowners across the state, including in Westchester.
Key California ADU Regulations:
- Size Limits: Detached ADUs can be up to 1,200 sq ft. Attached ADUs can be up to 50% of the primary dwelling or 1,200 sq ft, whichever is less. Junior ADUs (JADUs) can be up to 500 sq ft within the existing home footprint.
- Setbacks: 4-foot side and rear setbacks for new detached ADUs. Existing structures being converted (like garages) can maintain non-conforming setbacks.
- Height: Up to 16 feet for standard detached ADUs, 18 feet within a half-mile of transit, and up to 24 feet for two-story ADUs in qualifying zones.
- Parking: No additional parking required if the property is within a half-mile of a public transit stop. Otherwise, one space may be required. Tandem parking and mechanical lifts are allowed.
- Owner Occupancy: No owner-occupancy requirement for ADUs. Owner occupancy is required only for properties with a JADU.
- Approval Timeline: Cities must approve or deny ADU applications within 60 days.
- Impact Fees: ADUs under 750 sq ft are exempt from impact fees. Larger ADUs may be subject to proportionally reduced fees.
- Multiple ADUs: Single-family lots can have one ADU plus one JADU. Multi-family properties can add up to two detached ADUs or convert up to 25% of existing non-livable space.
Westchester-Specific ADU Considerations:
As a neighborhood within the City of Los Angeles, Westchester follows the City's ADU ordinance (LAMC Section 12.22 A.31), which implements state law with some local additions:
- Local Zoning: Predominantly R1 single-family residential. Commercial zones along Lincoln Blvd and Manchester Ave. LAX-related overlay zones may apply to some properties.
- Lot Characteristics: Westchester properties typically have lot sizes of 5,500-7,500 sq ft, which provides ample room for most ADU configurations.
- Common ADU Types: Detached backyard ADUs, Garage conversions, Junior ADUs are the most popular ADU approaches in Westchester.
- Garage Conversions: Standard two-car garages from 1940s-50s construction. Conversions are straightforward with the planned community's uniform lot layouts.
- Transit Access: While Westchester's transit score of 42 reflects more limited transit, properties near major bus routes may still qualify for parking exemptions.
- Rental Market: High demand with ADU rents typically ranging from $1,800-$2,800/month for studio/1BR ADU.
These regulations reflect the City of Los Angeles' commitment to increasing housing options while addressing Westchester's unique neighborhood characteristics. GatherADU specializes in navigating these regulations to design and build ADUs that comply with all local, city, and state requirements while maximizing value for homeowners.
Recent ADU Law Updates Affecting Westchester
California continues to update its ADU laws to further streamline the process and remove barriers for homeowners. Recent legislation that benefits Westchester property owners includes:
- AB 2221 (2023): Clarified that ADUs cannot be rejected based on the existing primary dwelling's non-conformity with current zoning. This is particularly beneficial for Westchester's older housing stock, where many homes may not fully conform to current zoning standards.
- SB 897 (2023): Increased height limits for ADUs, allowing up to 18 feet near transit and up to 24 feet for two-story ADUs in multi-family zones. Properties near transit stops in Westchester may qualify for the increased height limits.
- AB 976 (2024): Made the prohibition on owner-occupancy requirements for ADUs permanent. Westchester homeowners can rent both their primary home and ADU without living on the property.
- AB 434 (2024): Streamlined the ministerial approval process further, ensuring cities cannot impose unreasonable conditions on ADU applications.
ADU Permitting Tips for Westchester Homeowners
Successfully navigating the ADU permitting process in Westchester requires attention to several key areas:
- Pre-Submission Consultation: Before submitting plans, schedule a pre-review with LADBS or work with an experienced ADU builder like GatherADU who can identify potential issues early.
- Complete Documentation: Ensure your application includes all required documents including site plans, floor plans, elevations, Title 24 energy calculations, and structural calculations. Incomplete applications are the most common cause of delays.
- HOA Considerations: While California law prevents HOAs from outright prohibiting ADUs, some Westchester properties may be in communities with CC&Rs that require design review. HOAs cannot unreasonably restrict ADUs but may have input on aesthetic elements.
- Utility Coordination: Contact DWP (water and power) and the LA Bureau of Sanitation early in the process to determine if any utility upgrades are needed for your Westchester property.
- Timeline Management: The City must approve or deny your application within 60 days. If no decision is made within that period, your application is deemed approved under state law.
GatherADU has helped hundreds of Los Angeles homeowners navigate the ADU process, including many in the Westside area. Our team handles all aspects of design, permitting, and construction, ensuring your Westchester ADU project proceeds smoothly from concept to completion. Call (323) 591-3717 for a free consultation.
Your Rights Under California Law
California law (AB 68, AB 881, SB 9, and subsequent legislation) guarantees your right to build ADUs. Cities cannot:
- Require owner-occupancy for ADUs permitted after 2020
- Require additional parking for ADUs near transit
- Charge impact fees for ADUs under 750 sq ft
- Deny ADUs that meet state minimum standards
- Impose lot coverage limits that prevent a 800 sq ft ADU
If you believe your ADU application is being unfairly denied, California HCD can intervene on your behalf.
This information is for informational purposes only and does not constitute legal advice. Consult a qualified attorney for legal guidance.
About Westchester
Westchester is a distinctive neighborhood within the City of Los Angeles, located in Los Angeles County, California. Westchester is a family-friendly neighborhood built primarily for post-WWII aviation and aerospace workers, located adjacent to LAX. The area offers a suburban feel with excellent schools, parks, and proximity to Loyola Marymount University. Its location near LAX, Silicon Beach, and the coast makes it attractive for professionals. With a population of approximately 42,000 residents and a median household income of $85,000, Westchester represents an affluent community within the greater Los Angeles metropolitan area.
The neighborhood encompasses several zip codes including 90045, and is situated in the Westside region of Los Angeles. Westchester is surrounded by the neighborhoods of Playa del Rey, Marina del Rey, Inglewood (city), El Segundo (city), creating a connected urban fabric of diverse communities. The area's geographic coordinates (33.9592°N, -118.4148°W) place it on the desirable Westside of Los Angeles.
Key landmarks and attractions in Westchester include Westchester Recreation Center, Loyola Marymount University, Otis College of Art and Design (former site), and Westchester Elks Lodge. The area is known for its 1940s-50s post-war tract homes, Ranch-style homes, Split-level homes, with lot sizes typically ranging from 5,500-7,500 sq ft. The average home price in Westchester is approximately $1,200,000, and the median monthly rent is around $2,400.
For homeowners considering an Accessory Dwelling Unit (ADU) in Westchester, the neighborhood offers lax proximity creates strong demand from aviation industry workers and travelers. Additionally, lmu creates student and faculty rental demand. The high rental demand in the area, combined with rental prices ranging from $1,800-$2,800/month for studio/1BR ADU, makes ADU construction a highly lucrative investment for property owners. Common ADU types in Westchester include Detached backyard ADUs, Garage conversions, Junior ADUs.
The local economy is driven by Aviation and aerospace (LAX adjacent), Education (Loyola Marymount University), Silicon Beach tech companies, providing a diverse employment base that supports the rental market. The school district serving Westchester includes LAUSD - includes Westchester Enriched Sciences Magnet, Loyola Marymount University (private), contributing to the area's appeal for families.
Transit options in Westchester include Metro C Line (nearby stations), LAX FlyAway. The neighborhood has a walkability score of 58, a bike score of 55, and a transit score of 42, providing reasonable transit options for residents and potential ADU tenants.
Westchester's unique character, and high rental demand make it a highly attractive location for ADU investment in Los Angeles. Whether homeowners are looking to generate rental income, create multigenerational living arrangements, or add a home office studio, an ADU in Westchester offers substantial value.
More About Westchester
Westchester, California, is a neighborhood within the City of Los Angeles located in the Westside region of Los Angeles County. Westchester is a family-friendly neighborhood built primarily for post-WWII aviation and aerospace workers, located adjacent to LAX. The area offers a suburban feel with excellent schools, parks, and proximity to Loyola Marymount University. Its location near LAX, Silicon Beach, and the coast makes it attractive for professionals.
Geography and History
Situated at coordinates 33.9592°N, -118.4148°W, Westchester is positioned within the Westside area of Los Angeles. Developed in the 1940s by Fritz Burns (who also developed Panorama City) as housing for workers at nearby aircraft factories during WWII. The neighborhood's gridded streets and uniform lot sizes reflect its planned community origins.
The neighborhood is bordered by Playa del Rey, Marina del Rey, Inglewood (city), El Segundo (city), Playa Vista, creating a diverse tapestry of communities. Westchester's zip code is 90045.
Local Economy
Westchester's economy is driven by several key sectors that shape the neighborhood's character and employment landscape:
- Aviation and aerospace: Aviation and aerospace (LAX adjacent)
- Education: Education (Loyola Marymount University)
- Silicon Beach tech companies: Silicon Beach tech companies contributes to the local economy and provides employment opportunities for residents.
- Professional services: Professional services contributes to the local economy and provides employment opportunities for residents.
- Retail: Retail contributes to the local economy and provides employment opportunities for residents.
Housing Market and Real Estate
Westchester's real estate market features 1940s-50s post-war tract homes, Ranch-style homes, Split-level homes, Some newer custom homes, Condominiums near LMU. The average home price in Westchester is approximately $1,200,000, positioning it as a mid-range option in the competitive Los Angeles market. Lot sizes typically range from 5,500-7,500 sq ft, offering standard urban lot sizes that can accommodate well-designed ADUs.
The median rent in Westchester is approximately $2,400 per month, and the median household income is approximately $85,000. This rent-to-income ratio reflects a relatively balanced housing market, though ADUs still provide valuable additional rental inventory.
Transportation and Connectivity
Westchester offers several transportation options for residents and commuters:
- Metro C Line (nearby stations)
- LAX FlyAway
- Metro bus routes on Lincoln Blvd, Manchester Ave, Sepulveda Blvd
- LAX adjacent
The neighborhood has a walkability score of 58 out of 100, a bike score of 55, and a transit score of 42. While transit access is more limited, many residents rely on personal vehicles, making parking an important consideration in ADU planning.
Schools and Education
Westchester is served by LAUSD - includes Westchester Enriched Sciences Magnet, Loyola Marymount University (private). The neighborhood's educational institutions contribute to its family-oriented appeal and influence the rental market for ADUs, as families seeking quality schools often look for housing in the area.
ADU Regulations in Westchester
As a neighborhood within the City of Los Angeles, Westchester follows LA's ADU regulations, which align with and in many cases exceed California state law requirements. These regulations are designed to facilitate ADU development while addressing the city's critical housing needs.
- Zoning: Predominantly R1 single-family residential. Commercial zones along Lincoln Blvd and Manchester Ave. LAX-related overlay zones may apply to some properties.
- Types of ADUs: Both attached and detached ADUs are permitted, as well as Junior ADUs (JADUs) of up to 500 sq ft created within the existing footprint of the primary home.
- Size Limits:
- Detached ADUs: Up to 1,200 sq ft regardless of lot size (as of January 2025)
- Attached ADUs: Up to 1,200 sq ft or 50% of the primary dwelling's living area, whichever is less
- JADUs: Up to 500 sq ft
- Height Restrictions: Detached ADUs can be up to 16 feet, or 18 feet if within a half-mile of a major transit stop. Two-story ADUs up to 24 feet are allowed in some zones.
- Parking: Standard residential parking with driveways and garages. Street parking generally available on residential streets. One additional parking space may be required unless the property is within a half-mile of a transit stop.
- Owner Occupancy: No owner-occupancy requirement for ADUs built under California state law. Owner occupancy is required only for JADUs.
- Setbacks: 4-foot side and rear setbacks for detached ADUs. ADUs converting existing structures (like garages) may maintain existing non-conforming setbacks.
- Impact Fees: ADUs under 750 sq ft are exempt from impact fees in the City of LA. ADUs 750 sq ft and above may be subject to proportional fees.
- Design Standards: ADUs must meet Los Angeles Building Code requirements. The City encourages ADU designs that complement the existing primary dwelling and neighborhood character.
ADU Opportunities Specific to Westchester
Westchester presents unique opportunities for ADU development based on its neighborhood characteristics:
- LAX proximity creates strong demand from aviation industry workers and travelers
- LMU creates student and faculty rental demand
- Silicon Beach employment hub nearby drives professional renter demand
- Standard post-war lot sizes accommodate most ADU designs
- Some properties in LAX flight path - consider soundproofing for ADUs
- Metro C Line nearby provides transit access options
Common ADU Types in Westchester
Based on the neighborhood's lot sizes, zoning, and housing stock, the most common ADU types in Westchester include:
- Detached backyard ADUs: Detached backyard ADUs up to 1,200 sq ft take advantage of Westchester's lot sizes (5,500-7,500 sq ft) to create fully independent living spaces.
- Garage conversions: Standard two-car garages from 1940s-50s construction. Conversions are straightforward with the planned community's uniform lot layouts.
- Junior ADUs: Junior ADUs (up to 500 sq ft) created within the existing home footprint offer the most affordable entry point for ADU construction, typically requiring minimal new construction.
ADU Rental Market in Westchester
The rental demand in Westchester is rated as High, with ADU rental prices typically ranging from $1,800-$2,800/month for studio/1BR ADU. The strong rental demand ensures ADU owners can find quality tenants quickly, making ADU construction a sound financial investment.
Key factors driving Westchester's rental market include:
- Average home price of $1,200,000 keeps homeownership out of reach for many workers, sustaining rental demand
- Aviation and aerospace (LAX adjacent) and Education (Loyola Marymount University) provide a stable employment base of potential tenants
- Growing transportation options improve accessibility for ADU tenants
- Proximity to Playa del Rey and Marina del Rey extends the pool of potential tenants from surrounding areas
Cultural Landmarks and Unique Aspects
Westchester is known for several unique features that define its character and appeal:
- Adjacent to LAX airport
- Loyola Marymount University neighborhood
- Proximity to Silicon Beach tech hub
- Planned post-WWII community design
Why Build an ADU in Westchester?
Building an ADU in Westchester offers homeowners a compelling combination of financial return and community benefit:
- Strong Rental Income: With rents of $1,800-$2,800/month for studio/1BR ADU, an ADU can generate significant monthly income to offset mortgage costs or fund retirement
- Property Value Increase: ADUs typically add 25-40% of their construction cost to overall property value
- Housing Flexibility: An ADU can serve as rental income today and accommodate aging parents or adult children in the future
- Neighborhood Character: Westchester's 1940s-50s post-war tract homes housing stock and 5,500-7,500 sq ft lot sizes provide opportunities for thoughtfully designed ADUs that complement the existing neighborhood
- Community Need: Westchester's high rental demand reflects a genuine need for more housing, and ADUs provide gentle density that benefits the entire community
ADU Construction Process in Westchester
Building an ADU in Westchester involves several key phases, each requiring careful planning and expertise. Here is a detailed overview of what homeowners can expect when building an ADU in this Los Angeles neighborhood:
Phase 1: Feasibility Assessment and Site Evaluation
The first step in building an ADU in Westchester is determining what is possible on your specific property. This involves:
- Property Analysis: A thorough evaluation of your lot size (typical Westchester lots are 5,500-7,500 sq ft), existing structures, setback requirements, and utility connections. Even on standard-sized lots in Westchester, creative design solutions can maximize ADU living space.
- Zoning Verification: Confirming your property's zoning designation and any overlay zones that may apply. Predominantly R1 single-family residential. Commercial zones along Lincoln Blvd and Manchester Ave. LAX-related overlay zones may apply to some properties.
- Soil and Topography Assessment: Standard soil testing ensures the foundation design is appropriate for your specific lot conditions.
- Utility Assessment: Evaluating existing sewer, water, electrical, and gas connections to determine what upgrades may be needed for the ADU.
Phase 2: Design and Architecture
ADU design in Westchester should balance maximizing livable space with complementing the existing neighborhood character. Key design considerations include:
- Architectural Style: Westchester's housing stock includes 1940s-50s post-war tract homes, Ranch-style homes, Split-level homes. ADU designs that reference these architectural elements create a cohesive property appearance.
- Floor Plan Optimization: Whether building a studio, one-bedroom, or two-bedroom ADU, efficient floor plans are essential. Open-concept layouts, built-in storage, and multi-functional spaces help maximize the impact of every square foot.
- Indoor-Outdoor Connection: Even on compact Westchester lots, thoughtful design can incorporate small patios, decks, or courtyard spaces that extend the ADU's usable area.
- Privacy: Window placement, landscaping, and ADU orientation should be carefully planned to provide privacy for both the ADU occupants and the primary residence.
- Natural Light: Strategic window placement, skylights, and clerestory windows help ADUs feel spacious and airy, reducing the need for artificial lighting during daytime hours.
Phase 3: Permitting
The City of Los Angeles has streamlined its ADU permitting process in compliance with state law. For Westchester properties, the permitting process typically includes:
- Submitting plans to the Los Angeles Department of Building and Safety (LADBS)
- Plan check review (the city must approve or deny within 60 days under state law)
- Any required environmental or overlay zone reviews
- Building permit issuance
- Construction inspections at key milestones
- Final inspection and certificate of occupancy
The typical timeline from plan submission to permit approval in Los Angeles is 6-10 weeks, though actual timelines can vary based on project complexity and current department workload.
Phase 4: Construction
ADU construction in Westchester typically takes 5-8 months depending on the type and size of ADU:
- Garage Conversions: Standard two-car garages from 1940s-50s construction. Conversions are straightforward with the planned community's uniform lot layouts. Garage conversions are often the fastest and most affordable ADU type, typically completing in 3-5 months.
- Detached New Construction: Building a new detached ADU from the ground up provides maximum design flexibility but requires the longest construction timeline, typically 6-10 months.
- Junior ADUs (JADUs): Converting existing space within the primary home into a JADU can often be completed in 2-4 months, as the basic structure already exists.
- Prefabricated/Modular ADUs: Factory-built ADU modules can significantly reduce on-site construction time, with installation and finishing work often completed in 2-4 months after the foundation is prepared.
ADU Cost Estimates for Westchester
ADU construction costs in Westchester vary based on the type of ADU, size, finishes, and site conditions. Here are approximate cost ranges that Westchester homeowners can expect:
- Junior ADU (JADU) - Up to 500 sq ft: $60,000-$120,000. These conversions within the existing home footprint are the most affordable option.
- Garage Conversion - 400-600 sq ft: $80,000-$160,000. Converting an existing garage saves on foundation and framing costs.
- Detached ADU - 600-1,200 sq ft: $150,000-$350,000. New construction from the ground up offers the most flexibility but highest cost.
- Above-Garage ADU - 500-800 sq ft: $130,000-$280,000. Building above an existing or new garage maximizes lot usage.
- Prefabricated ADU - 400-1,200 sq ft: $120,000-$300,000. Factory-built modules offer consistent quality and faster timelines.
These estimates include design, permitting, construction, and standard finishes. Factors that can increase costs include challenging soil conditions, utility upgrades, and premium finishes. GatherADU provides detailed cost estimates specific to your Westchester property during the free consultation phase.
ADU Financing Options for Westchester Homeowners
Several financing options are available to Westchester homeowners looking to build an ADU:
- Home Equity Line of Credit (HELOC): With Westchester home values averaging $1,200,000, many homeowners have significant equity that can be leveraged to finance ADU construction. HELOCs offer flexible draw periods and competitive interest rates.
- Cash-Out Refinance: Refinancing your primary mortgage to pull out equity for ADU construction can be advantageous when interest rates are favorable, particularly for Westchester properties with strong appreciation.
- Construction Loans: Short-term construction loans provide funding during the building phase and can be converted to permanent financing upon completion.
- CalHFA ADU Grant Program: California's Housing Finance Agency offers grants of up to $40,000 for pre-development costs (design, permits, soil tests) for ADU projects, available to qualifying homeowners in Westchester.
- LA County ADU Accelerator Program: Los Angeles County has programs designed to assist homeowners with ADU development, including technical assistance and potential financial support.
- Personal Savings: For smaller projects like JADUs or garage conversions, personal savings may cover a significant portion of the construction cost.
The return on investment for an ADU in Westchester is compelling: with ADU rents of $1,800-$2,800/month for studio/1BR ADU, homeowners can expect to recoup their investment in 7-12 years through rental income alone, while also benefiting from increased property value.
ADU Design Ideas for Westchester Properties
The architectural character of Westchester inspires several ADU design approaches that complement the neighborhood while meeting modern living standards:
- 1940s-50s post-war tract homes Companion: ADUs designed to match the 1940s-50s post-war tract homes architecture common in Westchester create visual harmony between the primary dwelling and the accessory unit. Using similar materials, roof pitches, and design details ensures the ADU feels like a natural extension of the property.
- Modern Contrast: Some Westchester homeowners opt for a contemporary ADU design that intentionally contrasts with the primary home's traditional architecture, creating visual interest while maintaining scale and proportion.
- Indoor-Outdoor Living: The Westside's temperate coastal climate is ideal for ADUs with strong indoor-outdoor connections, including large glass doors, decks, and garden access.
- Sustainable Design: Energy-efficient ADU designs are increasingly popular in Westchester, incorporating solar panels, energy-efficient appliances, tankless water heaters, LED lighting, and drought-resistant landscaping. California's Title 24 energy code ensures all new ADUs meet high efficiency standards.
- Aging-in-Place Features: ADUs designed for multigenerational living may include single-story layouts, wider doorways, curbless showers, grab bars, and other universal design features that accommodate residents of all ages and abilities.
Frequently Asked Questions About ADUs in Westchester
Q: How long does it take to build an ADU in Westchester?
A: The total timeline from initial design to move-in typically ranges from 8-14 months for a detached ADU in Westchester. This includes approximately 2-3 months for design and permitting, and 5-8 months for construction. Garage conversions and JADUs can be completed more quickly, often in 5-8 months total.
Q: Do I need to live on the property to build an ADU in Westchester?
A: Under current California law, there is no owner-occupancy requirement for ADUs. You do not need to live in either the primary dwelling or the ADU. However, if you build a Junior ADU (JADU), owner occupancy in either the JADU or the primary home is required.
Q: Can I rent out my ADU on Airbnb or as a short-term rental in Westchester?
A: Short-term rental regulations vary. The City of Los Angeles has specific rules regarding short-term rentals that may limit ADU use for platforms like Airbnb or VRBO. As of the most recent ordinance, ADUs used as short-term rentals must comply with the Home-Sharing Ordinance. Long-term rentals (30+ days) are generally unrestricted for ADUs.
Q: What is the maximum size ADU I can build on my Westchester property?
A: Under California law, detached ADUs can be up to 1,200 sq ft regardless of your lot size. Attached ADUs can be up to 1,200 sq ft or 50% of the primary dwelling's living area, whichever is less. JADUs are limited to 500 sq ft. With Westchester's typical lot sizes of 5,500-7,500 sq ft, most properties can accommodate a full-size 1,200 sq ft ADU.
Q: How much will an ADU increase my property value in Westchester?
A: In the Westchester market, ADUs typically add 25-40% of their construction cost to overall property value. With average home prices at $1,200,000 and ADU rental income of $1,800-$2,800/month for studio/1BR ADU, the income-generating potential also contributes significantly to the property's appraised value, particularly when assessed using the income approach.
Q: Will I need to provide parking for my ADU in Westchester?
A: Properties within a half-mile of a public transit stop are exempt from parking requirements. Properties farther from transit may need to provide one parking space for the ADU, though garage conversions are exempt from replacement parking requirements.
Neighborhood Comparison: Westchester vs. Nearby Areas
Understanding how Westchester compares to neighboring communities helps homeowners evaluate their ADU investment:
- Westchester vs. Playa del Rey: Westchester's average home price of $1,200,000 and lot sizes of 5,500-7,500 sq ft may be higher than Playa del Rey, while its high rental demand ensures strong ADU returns.
- Westchester vs. Marina del Rey: Both neighborhoods share Westside characteristics, but Westchester's unique features including adjacent to lax airport distinguish its ADU market.
- Westchester vs. Inglewood (city): Westchester's transit score of 42 and walkability of 58 reflects its distinct character, and each neighborhood offers different advantages for ADU investment.
Getting Started with Your Westchester ADU Project
Westchester's ADU regulations aim to support housing development while maintaining the neighborhood's unique character. With its adjacent to lax airport, loyola marymount university neighborhood, and high rental demand, Westchester offers a compelling case for ADU construction. Whether you're building a detached backyard unit, converting a garage, or creating a junior ADU within your existing home, GatherADU can guide you through every step of the process — from design through permits to finished construction.
GatherADU has extensive experience building ADUs throughout the Westside area of Los Angeles, including in Westchester and neighboring communities like Playa del Rey, Marina del Rey, Inglewood (city). Our team understands the unique requirements and opportunities that Westchester properties present, and we can help you navigate local zoning rules, and the full permitting process.
Contact GatherADU today at (323) 591-3717 or visit gatheradu.com/contact to schedule your free ADU consultation and discover the potential of your Westchester property.
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Types of ADUs You Can Build in Westchester
California law allows several types of accessory dwelling units on residential properties. Understanding your options helps you choose the best approach for your property and goals.
Detached ADU
A standalone structure built separately from your main house, typically in the backyard. Detached ADUs offer maximum privacy for both homeowners and tenants, with their own entrance, walls, roof, and complete living facilities. In Westchester, detached ADUs can be up to 1,200 square feet and 16 feet tall. This option provides the most flexibility in design and placement, though it typically costs more than conversions due to new construction requirements.
- Max Size: Up to 1,200 sq ft
- Height: Up to 16 feet
- Setbacks: 4 ft from side/rear lines
- Best For: Maximum rental income, privacy
Attached ADU
An addition built onto your existing home, sharing at least one wall with the primary residence. Attached ADUs are often more cost-effective than detached units because they can leverage existing foundation, roof structure, and utility connections. They work well on properties with limited backyard space or where you want to minimize the visual impact of new construction. Many homeowners choose attached ADUs for aging parents who want proximity while maintaining independence.
- Max Size: Up to 1,200 sq ft
- Height: Matches main home
- Setbacks: Same as main structure
- Best For: Limited lot space, family housing
Garage Conversion ADU
Transform your existing garage into a complete living space. Garage conversions are often the most affordable ADU option in Westchester because the basic structure already exists. You save on foundation, framing, and roofing costs while creating a valuable rental unit or family living space. California law prohibits cities from requiring replacement parking when you convert a garage to an ADU, making this option particularly accessible. Most garage conversions result in studios or one-bedroom units ranging from 400 to 600 square feet.
- Typical Size: 400-600 sq ft
- Timeline: 3-5 months typical
- Cost: 30-50% less than new construction
- Best For: Budget-conscious, quick timeline
Junior ADU (JADU)
A smaller unit of up to 500 square feet created within your existing home's footprint, typically by converting a bedroom, basement, or attached garage. JADUs must include a cooking facility (at minimum, a sink, counter, and small appliance outlet) but can share a bathroom with the main house. In Westchester, you can build both a JADU and a full ADU on the same property, maximizing your housing options. JADUs require owner-occupancy in either the main house or the JADU itself.
- Max Size: 500 sq ft
- Location: Within existing home
- Requirements: Owner-occupancy required
- Best For: Minimal construction, family use
Above-Garage ADU
Build a new living unit above your existing or new garage structure. This two-story approach preserves your parking while adding living space above. In Westchester, above-garage ADUs can reach 18-20 feet in height depending on distance from property lines. This option is particularly popular in neighborhoods with narrow lots where backyard space is limited. The elevated position often provides better views and natural light than ground-level units.
- Max Size: Up to 1,200 sq ft
- Height: Up to 18-20 feet
- Parking: Preserved below unit
- Best For: Limited lot space, maintaining parking
Basement Conversion
While less common in Southern California due to construction patterns, properties with existing basements can convert that space into an ADU. Basement conversions require proper egress windows, adequate ceiling height (at least 7 feet in habitable areas), and may need waterproofing and ventilation upgrades. When properly executed, basement ADUs provide naturally cool living space and complete separation from the main home's daily activities.
- Max Size: Existing footprint
- Requirements: Egress, ceiling height
- Benefits: Cool temps, full separation
- Best For: Existing basements only
Complete ADU Services in Westchester
From initial feasibility analysis through final inspection, we handle every aspect of your ADU project. Our Westchester-focused approach ensures your project meets all local requirements while maximizing value.
Feasibility Analysis
We begin every project with a comprehensive analysis of your property's ADU potential. Our team reviews your lot size, zoning, setbacks, utility connections, and neighborhood context to determine what you can build. In Westchester, this includes understanding any overlay zones, historic district requirements, or other local factors that might affect your project. You receive a detailed report showing your options, estimated costs, and potential rental income before committing to design work.
- Property zoning verification
- Setback and lot coverage analysis
- Utility capacity assessment
- Cost and ROI projections
Design & Architecture
Our design team creates ADU plans tailored to your property and goals. Whether you want a modern studio for maximum rental income or a two-bedroom unit for family members, we design spaces that work. We understand Westchester architectural context and create designs that complement existing homes while meeting all building code requirements. Every design includes structural engineering, Title 24 energy compliance, and all documentation needed for permits.
- Custom floor plan development
- 3D renderings and visualizations
- Structural engineering
- Energy compliance documentation
Permitting & Approvals
Navigating Westchester permitting can be complex, but we handle it all. Our team prepares complete permit applications, manages plan check submissions, and coordinates with building department staff to address any comments or corrections. We track your application through the approval process and keep you informed of progress. Our experience with Westchester regulations helps avoid common pitfalls that delay other projects.
- Complete permit application prep
- Plan check management
- Building department coordination
- Permit tracking and updates
Construction
Our licensed construction team builds your ADU with quality materials and skilled craftsmanship. We handle all aspects of construction including foundation, framing, electrical, plumbing, HVAC, insulation, drywall, flooring, cabinets, and finishes. Throughout the build, we coordinate required inspections, manage subcontractors, and keep you updated on progress. Our goal is delivering a finished ADU that exceeds your expectations while respecting your timeline and budget.
- Licensed general contractor
- Quality materials and finishes
- Inspection coordination
- Project management and updates
Interior Design
A well-designed interior maximizes both livability and rental appeal. Our interior design services help you select finishes, fixtures, and colors that create appealing spaces within your budget. We offer curated finish packages at different price points, or work with you to customize selections. From kitchen layouts that maximize counter space to bathroom designs that feel spacious, we sweat the details that make small homes work beautifully.
- Finish and fixture selection
- Space planning optimization
- Curated design packages
- Custom interior options
Financing Guidance
We help connect you with financing options suited to your situation. Many Westchester homeowners use home equity, construction loans, or specialized ADU financing products to fund their projects. We can introduce you to lenders experienced in ADU financing and help you understand options including cash-out refinancing, HELOCs, and construction-to-permanent loans. While we're not lenders ourselves, our guidance helps you navigate financing decisions confidently.
- Financing option overview
- Lender introductions
- ROI and cash flow projections
- Budget planning assistance
How We Build Your Westchester ADU
Our streamlined process takes you from initial concept to move-in ready ADU. Here's what to expect at each stage of your project.
Free Consultation
We start with a free consultation to understand your goals, assess your property, and explain your options. This can happen via phone, video call, or an in-person site visit in Westchester. You'll learn what you can build, approximate costs, and timeline expectations.
Feasibility Study
Our team conducts a thorough analysis of your Westchester property. We verify zoning, calculate setbacks and lot coverage, assess utility connections, and identify any site-specific considerations. You receive a written report with your ADU options.
Design Development
Working with our architects and designers, you'll develop floor plans, select exterior styles, and make finish selections. We create 3D renderings so you can visualize the finished ADU before construction begins.
Permitting
We submit your complete permit application to Westchester and manage the entire approval process. This includes responding to plan check comments and coordinating with building department staff through to permit issuance.
Construction
With permits in hand, construction begins. Our crews work efficiently while respecting your property and neighbors. For a typical Westchester ADU, construction takes 4-6 months. You'll have a dedicated project manager throughout the build.
Walkthrough & Move-In
We conduct a detailed walkthrough, demonstrate systems and appliances, and address any punch list items. Once final inspections are complete, you receive your certificate of occupancy. Your new Westchester ADU is ready.
ADU Costs in Westchester
Understanding ADU costs helps you plan realistically and evaluate the investment opportunity. Here's what to expect for typical Westchester ADU projects.
Garage Conversion
$100,000 - $180,000Converting an existing garage is typically the most affordable path to an ADU. You save on foundation and framing since the basic structure exists. Costs vary based on garage condition, size, and finish level desired. Most garage conversions in Westchester result in studios or one-bedroom units between 400-600 square feet.
- Electrical and plumbing installation
- HVAC system
- Insulation and drywall
- Kitchen and bathroom
- Flooring and finishes
- Permits and inspections
Detached New Construction
$200,000 - $400,000Building a new detached ADU involves complete construction from the ground up. This option costs more but offers maximum design flexibility and typically commands higher rents. A one-bedroom detached ADU in Westchester typically costs $200,000-$280,000. Two-bedroom units range from $280,000-$400,000 depending on size and finishes.
- Foundation and site work
- Complete framing and roofing
- All mechanical systems
- Interior and exterior finishes
- Utility connections
- Design, engineering, permits
Attached Addition
$150,000 - $300,000Attached ADUs share a wall with your existing home, which can reduce some construction costs. You may be able to tie into existing roof structure and foundation, though this depends on your home's configuration. Costs fall between garage conversions and fully detached new construction for most Westchester projects.
- Foundation extension (if needed)
- Framing and roofing integration
- Separate entrance and utilities
- Complete interior buildout
- Fire separation requirements
- Permits and inspections
Return on Investment
Actual rents depend on unit size, finishes, location within Westchester, and current market conditions. One-bedroom ADUs typically rent higher than studios; two-bedroom units command premium rates.
According to Freddie Mac research, ADUs add 20-30% to property values in high-demand California markets. This often exceeds construction costs, creating immediate equity.
When you factor rental income against construction costs, many Westchester ADUs generate 8-12% annual cash-on-cash returns, competitive with or exceeding other investment options.
Frequently Asked Questions About ADUs in Westchester
Get answers to the most common questions about building an accessory dwelling unit in Westchester.
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