As of October 2026, the closest published benchmark is Block Renovation's 2026 Sacramento guide: about $150,000 to $300,000 or more for a detached ADU, $80,000 to $150,000 for a garage conversion and $50,000 to $100,000 for a junior ADU. We found no Fresno-only figure. Your lot, utilities and size set the real price.
What do published 2026 cost guides say?
We did not find a reputable source that tracks Fresno ADU prices alone, so we use the nearest Central Valley figures, as of October 2026.
| ADU type | Published range |
|---|---|
| Junior ADU (up to 500 sq ft) | $50,000 to $100,000 |
| Garage conversion | $80,000 to $150,000 (about $150 to $250 per sq ft) |
| Attached ADU | $100,000 to $300,000 |
| Detached ADU | $150,000 to $300,000 or more (about $300 to $500 per sq ft) |
RenoFi's September 2026 guide gives a wider national spread of about $150 to $600 per sq ft. Treat every range as a starting point, not a quote.
Which ADU type costs the least?
Usually a junior ADU or a garage conversion, because both reuse an existing structure. A detached ADU needs a new foundation, framing, roof and longer utility runs, so it tends to cost the most.
See garage conversions and detached ADUs for what each involves.
Can Fresno's free plans lower the cost?
Yes, on the design side. As of October 2026, the City of Fresno offers five pre-approved ADU plans, and its 2023 Quick Start Guide lists the plans and plan check as free, with building permits of up to $2,400 at that time.
The city also publishes a pre-approved ADU cost estimator spreadsheet. Construction, utilities and site work still cost what they cost. More in our free plans guide.
What drives the price of a Fresno ADU?
- Size and layout. Every bathroom and kitchen adds plumbing and fixtures.
- Electrical service. A panel or service upgrade is a common surprise in older homes.
- Sewer and water. Distance from the house and the depth of the sewer line matter.
- Cooling and energy. Title 24 rules, insulation and a heat pump or mini-split, plus solar on new detached units.
- Site access. A narrow side yard can mean hand-carrying materials.
- Finishes. Cabinets, flooring and windows move the total in either direction.
Which fees does state law limit?
As of October 2026, Government Code §66311.5 bars impact fees on an ADU of 750 sq ft or less and on a junior ADU of 500 sq ft or less, and school fees cannot be charged on units under 500 sq ft.
Larger ADUs pay impact fees in proportion to their size. A converted ADU or JADU is not treated as a new residential use for utility connection charges unless it is built with a new home. Plan check and building permit fees still apply.
How much do design and permits add?
Block Renovation's 2026 Sacramento guide estimates $14,000 to $20,000 for design, engineering and Title 24 work on a 600 sq ft detached ADU, and $2,000 to $8,000 in permits and fees for a unit under 750 sq ft.
It also recommends a 10 to 20 percent contingency. Using a city plan, where one fits, can cut the design line substantially.
When does the price depend most on your lot?
It depends on what is under the ground and behind the walls. Two ADUs with the same plan can differ by tens of thousands of dollars if one needs a new electrical service, a longer sewer run or slab repair. That is why we visit, open the panel and trace the sewer route before we give you a written, itemized quote.
Related
Sources, as of October 2026: Block Renovation, "Sacramento ADU Costs 2026: Types, Value, and Budget" (June 29, 2026); RenoFi, "ADU Cost Per Square Foot" (updated September 21, 2026); City of Fresno ADU Program page and ADU Quick Start Guide (October 2023); California Government Code §66311.5; HCD ADU Handbook (March 2026). These are published estimates, not quotes from us.
Updated October 2026