An accessory dwelling unit is a complete dwelling placed on a property that already has its own constraints. The useful first question is not which floor plan looks best. It is which ADU path fits the property, the intended use, and the applicable approval process.
A builder should help separate feasibility from preference before detailed design advances.
Begin with the property
Collect the property address, available surveys, existing plans, permit history, photographs, and information about utilities. Review access, existing structures, trees, grade, drainage, service locations, and the relationship between the proposed unit and the primary home.
City of Los Angeles properties can have parcel-specific zoning and overlay information in ZIMAS. LADBS provides plan-review, permitting, inspection, and property-record services. A builder should identify which questions require the local agency or a design professional instead of making a universal promise.
Compare the physical ADU paths
An ADU may use an existing structure, attach to the primary home, or stand separately. Each path changes the investigation.
A conversion depends on the condition, dimensions, and legal history of the existing structure. An attached unit must coordinate structure, enclosure, and building systems with the home. A detached unit creates its own foundation, enclosure, and utility-routing questions.
Do not choose the path from a generic cost ranking. Compare the actual property work required by each option.
Understand the current state review framework
California HCD's March 2026 ADU Handbook says a permitting agency must provide a written completeness determination no later than 15 business days after receiving an ADU or JADU application. If an existing single-family or multifamily dwelling is on the lot, the agency generally must approve or deny a completed application within 60 days.
Those review periods do not equal the full project duration. Property research, design, engineering, corrections, utility coordination, procurement, construction, inspections, and certificate of occupancy remain separate work.
State rules also interact with local objective standards and, where applicable, coastal requirements. Use the current HCD handbook and the responsible local agency for the specific property.
Ask how the builder defines scope
The candidate scope should distinguish among:
- Feasibility and property research.
- Survey, design, and consultant work.
- Permit and agency coordination.
- Site access and protection.
- Demolition or conversion work.
- Foundation and structural work.
- Water, sewer, electrical, gas, and mechanical systems.
- Energy-code documentation.
- Interior and exterior finishes.
- Inspections, corrections, and closeout.
Ask which items are included, excluded, allowances, or owner responsibilities.
Test the site plan before the finish plan
The location of the unit affects privacy, circulation, construction access, utilities, drainage, and the way the property will work after completion. Resolve those relationships before spending time on detailed finishes.
Hillside or constrained sites may need added technical review. Coastal properties may involve a concurrent coastal approval process. None of those conditions should be inferred from the neighborhood name alone. They must be checked for the parcel and the proposed scope.
Questions to ask the builder
- What property records and site information are needed before feasibility can be discussed? 2. Which ADU configurations deserve comparison on this lot? 3. Who owns design, engineering, energy, utility, and permit coordination? 4. What remains unknown until investigation or agency review? 5. How will scope changes be documented? 6. Which completed ADU is comparable, and what was the builder's verified role?
Make the first decision smaller
The first decision is not whether to build the whole project. It is whether the property and intended use justify a controlled feasibility step. A useful feasibility return identifies plausible configurations, open technical questions, responsible agencies, required specialists, and the next decision.
Related Jencor planning pages
Sources
- California HCD, Accessory Dwelling Unit Handbook, March 2026
- Los Angeles City Planning, ZIMAS
- Los Angeles Department of Building and Safety
Plan for cost and home value
Compare remodeling scope, published cost examples and the difference between estimated resale recovery and value while you own the home. The guide includes dated Los Angeles benchmarks and long-term planning considerations.
Compare accessory dwelling units costs and value
Related Jencor services
These service pages connect the planning topic to the project options, construction scope, and next steps Jencor can review.
Related reading
- Detached vs. Attached vs. Junior ADU: How to Choose
- Garage Conversion ADU Planning Checklist for Los Angeles
- What Drives ADU Cost in Los Angeles?
Questions
What is the first step in planning a Los Angeles ADU?
Start with property-specific feasibility, including records, access, utilities, site constraints, and plausible attached, detached, or conversion paths.
Do agency review periods equal the full ADU schedule?
No. Agency review periods do not include all design, investigation, correction, utility, procurement, or construction time.
How should I compare ADU builders?
Compare how each builder tests feasibility, defines scope, coordinates utilities and specialists, documents assumptions, and manages site logistics.
Planning a project in Los Angeles? Send Corey a note or call (310) 770-7707. Rules and requirements depend on the specific property; confirm with the city or county before you build.