Cost Guide

ADU Construction Cost in San Diego: Real Numbers for 2026

ADU Construction costs in San Diego, with budget ranges, permits, timeline, and contractor guidance from Cali Dream Construction.

Cost Snapshot

Budget project$150,000 to $240,000
Mid-range project$240,000 to $400,000
High-end project$400,000 to $650,000+
Typical planning contingency10% to 15%
Permit and plan review allowance1% to 4% of construction value when permits apply

Final cost depends on drawings, finish selections, utility work, structural changes, and permit scope. Use this as a planning range before a site-specific estimate.

What Drives Cost In San Diego

  • Detached ADUs cost more than many garage conversions because they need foundation, envelope, and utility work.
  • Sewer, electrical panel, trenching, and fire separation can change the budget materially.
  • Plan review, coastal overlays, and site access affect timeline and carry cost.
  • Rental-ready finishes, durable flooring, and storage add long-term value.

How To Keep The Budget From Drifting

Lock selections early, separate must-have scope from optional upgrades, and review allowances before signing. The biggest overruns usually come from vague finish allowances, structural surprises, and permit-driven plan changes.

Cali Dream Construction prices these conversations around real scope so a homeowner can compare options without bait-and-switch numbers.

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