Before You Hire
Before Hiring an ADU Builder in California
Questions to ask before paying deposits, signing design-build agreements, or relying on an early ADU estimate in California.
Why builder selection starts with property research
A builder may be excellent, but the project path still depends on the parcel, city or county jurisdiction, zoning, utilities, fire access, overlays, and permit review. Start by confirming what the property can support before comparing design-build proposals.
Questions about local experience
Ask whether the builder has completed ADUs in this city or county, which department reviewed those projects, whether they know the local ADU process, and whether they have handled hillside, fire, coastal, historic, or utility-constrained sites nearby.
Questions about scope
Ask whether the proposal covers design only, design-build, or full construction. Confirm whether engineering, Title 24, structural calculations, energy forms, permit corrections, utility coordination, meter upgrades, sitework, grading, drainage, retaining walls, driveways, and trenching are included or excluded.
Questions about permits
Ask who prepares permit drawings, who submits to the city or county, who responds to corrections, who attends inspections, and what happens if the local department requires revisions.
Questions about pricing and timeline
Ask what is included, what is excluded, what assumptions are being made, what can trigger change orders, how progress payments are structured, and which timeline pieces depend on city review, utilities, inspections, or site conditions.
Verification checklist
Check license, insurance, references, written contract scope, payment schedule, lien releases, change order policy, warranty, cancellation terms, and whether each estimate clearly names assumptions and exclusions.
Red flags
Be cautious with vague estimates, no written scope, pressure to sign before zoning review, permit-guarantee claims, unexplained utility or sitework exclusions, no local jurisdiction experience, or unclear payment schedules.
Practical checklist
Use this topic to organize a parcel-specific checklist before spending money: identify the APN, confirm jurisdiction, verify zoning and overlays, check utility and access facts, collect official links, and record department responses.
Red flags to watch
Treat the project as higher uncertainty if jurisdiction is unclear, utilities are not confirmed, sewer is unavailable, septic or well review is needed, the parcel is rural, road access is private, or fire, flood, coastal, slope, habitat, agricultural, or easement constraints may apply.
- Call planning before buying land or ordering plans.
- Ask building how the structure type will be reviewed.
- Confirm utility providers and connection feasibility.
- Check environmental health for septic and well issues.
- Ask the fire authority about access, hydrants, fire flow, WUI, and defensible space.
- Save links, names, dates, and code references.
Official verification
Use this article as an educational starting point only. The actual answer depends on parcel facts, local interpretation, official maps, utilities, fire authority standards, environmental health review, and building department requirements.
Frequently Asked Questions
Is there one statewide answer for this issue?
No. California rules create starting points, but parcel-specific local confirmation is required.
Which department should I contact first?
Start with the planning department for the parcel's city or unincorporated county area, then confirm building, utility, environmental health, and fire authority requirements as needed.
Can I rely on this guide instead of contacting local officials?
No. Use this guide to organize questions and documents, then confirm the answer directly with the appropriate local departments before spending money or submitting plans.
Related next steps
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Related county guides
Related city guides
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Review Next Steps
Use the county, city, and learning guides to organize zoning, utility, septic, fire access, estimate-readiness, and permit questions before buying land or choosing a design.
TinyHomeNavigator provides educational information only. Rules vary by parcel, zoning district, city, county, overlay, utility provider, fire authority, and environmental health department. Always confirm directly with the local planning department, building department, environmental health department, fire authority, and utility providers before buying land, designing, permitting, placing, or building any structure.