Yes. As of October 2026, Stanislaus County and nine partner cities, including Modesto, offer free pre-drawn plans for detached ADUs with several exterior finishes. The county's page lists 405, 744 and 1,192 sq ft plan sets, and partner cities list more sizes. You still pay for the permit, site drawings and construction.
Which cities share the plans?
The county lists Ceres, Hughson, Modesto, Newman, Oakdale, Patterson, Riverbank, Turlock and Waterford as partners, along with unincorporated Stanislaus County.
Ceres, Modesto, Oakdale, Riverbank, Turlock and Waterford built the original set with the county; Hughson, Newman and Patterson joined later, according to Westside Connect.
What sizes are available?
Lists differ by page. The county's current page shows 405, 744 and 1,192 sq ft sets, built to the 2025 California Building Code, with the 1,192 sq ft set marked as available soon.
Turlock's page links eight sizes: 260, 405, 562, 744, 798, 896, 1,050 and 1,192 sq ft. Ceres lists five named plans from 260 to 896 sq ft. We confirm which sets your city accepts when we file.
What does a pre-drawn plan replace?
The building design drawings. Turlock, for example, does not require a separate floor plan, foundation and framing plans, elevations, stamped engineering, MEP plans or Title 24 calculations for a pre-drawn plan.
What do I still submit?
A permit application, a scaled plot plan of your lot, and site-specific items such as truss calculations, solar plans for a new detached unit and sprinkler plans if the main house has them.
Can the plans be used for a garage conversion?
No. The program covers detached new construction. Conversions, attached ADUs and junior ADUs need drawings of your actual house or garage.
Our plans and permits page covers that route.
When is a custom plan worth it?
It depends on your lot and how you will use the unit. A narrow or irregular yard, a specific accessible layout or a size the set does not offer all point to custom drawings. Where a regional plan fits, it usually saves design time and money.
Related
Sources, as of October 2026: Stanislaus County ADU page; City of Turlock ADU Pre-Drawn Plans page; City of Ceres ADU page; City of Modesto news release (March 7, 2025); Westside Connect, "Stanislaus County, nine cities partner to streamline ADU master plans."
Updated October 2026