A June 2026 Sacramento guide from Block Renovation puts detached ADUs at about $150,000 to $300,000 or more and garage conversions at about $80,000 to $150,000, with per-square-foot figures of about $300 to $500 for detached units and $150 to $250 for conversions. Free city plans can lower design costs.
Published ranges
| ADU type | Published range |
|---|---|
| Junior ADU | About $50,000 to $100,000 |
| Garage conversion | About $80,000 to $150,000 |
| Attached ADU | About $100,000 to $300,000 |
| Detached ADU | About $150,000 to $300,000 or more |
These are published ranges, not a quote for your lot.
What moves the number?
- Utility runs. Distance to the sewer and whether the electrical panel needs an upgrade.
- Foundation and soil. Slopes, expansive soil and tree roots.
- Size and finishes. Kitchens and bathrooms carry the most cost per square foot.
- Access. Narrow side yards slow every delivery.
- Fees. Plan check and permit fees, plus school or utility fees on larger units.
What lowers it?
- Staying at 750 square feet or less, where California waives impact fees.
- A simple roofline and a plan that fits the setbacks without custom engineering.
- Converting existing space instead of building new, when the structure is sound.
Sources, checked November 2026: Block Renovation, "Sacramento ADU Costs 2026: Types, Value, and Budget" (June 29, 2026). Published ranges, not a quote.
Updated November 2026