Sacramento ADU Cost Calculator
Get an instant cost estimate for your ADU project in Sacramento or Placer County. Based on real 2026 construction data from local builders, permit fees, and market rates.
Estimated Total Cost
Midpoint: $269,000 · $400/sqft
Investment Return Estimate
Understanding ADU Costs in Sacramento (2026)
Building an Accessory Dwelling Unit in Sacramento County typically costs between $80,000 and $400,000+, depending on the type, size, and finish level. The Sacramento region has seen steady ADU construction growth since California's landmark ADU legislation (AB 68 and SB 13) streamlined the permitting process.
Garage conversions remain the most affordable option at $130–$250 per square foot, since the basic structure already exists. Detached ADUs are the most popular choice, offering maximum privacy and flexibility at $300–$500 per square foot. Prefab and modular ADUs have emerged as a middle-ground option, with factory-built units typically costing $180–$350 per square foot and offering faster construction timelines.
Sacramento County permit fees include a base building permit ($5,000+), plan check fees (~$8/sqft), and development impact fees (~$12,000 for units over 749 sqft). Under California law, ADUs of 749 square feet or less are exempt from impact fees — a significant savings that makes smaller units particularly cost-effective.
The CalHFA ADU Grant Program offers up to $40,000 in reimbursement for pre-development costs including permits, design, and soil tests. Combined with HELOC financing or construction loans, many Sacramento homeowners are building ADUs with minimal upfront cash.