Approval time is not the whole timeline
The first mistake is treating an approval deadline as a move-in date. California law includes processing protections for qualifying ADU applications, but a statutory review period is not a guarantee of completed construction. Application completeness, corrections, related approvals, utility work and procurement still affect the schedule. A useful calendar distinguishes those steps rather than compressing them into a single promise.
Begin with the intended use and the property, not a delivery date attached to an appealing floor plan. A detached dwelling, an attached unit and a conversion of existing space involve different conditions. Ask the designer to identify the applicable approval pathway and explain the current rules supporting it. HCD guidance, LADBS resources and property-specific zoning information should be read together.
A standard plan does not settle the site
LADBS’s approved standard-plan program can reduce repetitive design review. It does not establish that a selected design can be placed on any parcel without further evaluation. Property-specific zoning and foundation needs still require attention, and utility or other site issues may remain. Compare the plan’s advantages with the adjustments your property actually needs.
Before fixing dimensions, review existing structures, easements, slopes, drainage, trees and construction access. Confirm property lines rather than treating fences as surveyed boundaries. For a garage conversion, investigate both permit records and physical conditions. These are feasibility questions, not details to postpone until a crew is ready. An early footprint guarantee is not a substitute for that investigation.
Utilities and decisions belong on the calendar
Investigate electrical capacity, water service, sewer routing and heating and cooling equipment early. Ask whether upgrades, trenching, separate equipment or provider coordination are expected. Requirements vary by project type and applicable law, so obtain current information from the relevant providers. A construction schedule should acknowledge that work rather than assume infrastructure is already resolved.
Access matters as well. A narrow side yard can change delivery, excavation, staging and waste-removal methods. Meanwhile, layout, equipment and major finish decisions need agreed deadlines. Design, permitting and purchasing can precede site work by weeks or months; some activities overlap and others cannot. Ask for a scope-specific schedule showing assumptions, a sensible start and a working completion target.
Completion includes permission to occupy
Assign responsibility for applications, correction responses, permits, inspections and final documents before construction. Keep required inspection stages visible and document changes in writing, including their schedule effects. Functioning appliances and finished surfaces do not establish that the unit is ready for lawful occupancy. Verify final approvals and any applicable occupancy documentation.
Finally, test the ownership plan against delay. Insurance, financing, maintenance and utility arrangements deserve attention before handover, and projected rental income should not be treated as guaranteed. A realistic ADU timeline makes the dependencies visible and leaves the household with a plan if completion arrives later than expected. Check current requirements through the official sources linked in the related guides.