ADU Rules: Sonora vs Twain Harte
How do adu rules rules compare between Sonora, CA and Twain Harte, CA?
Sonora and Twain Harte have similar restriction levels.
Sonora, CA
Tuolumne County
Sonora must allow ADUs per California Government Code section 65852.2. State law permits detached ADUs up to 1,200 square feet with 4-foot side and rear setbacks and 16-foot height limit. ADUs cannot be used as short-term rentals under Chapter 17.64.
View full Sonora rules →Twain Harte, CA
Tuolumne County
Twain Harte is unincorporated, so Tuolumne County Ordinance Code Chapter 17.36 governs accessory dwelling units, layered on California's statewide ADU preemption (Gov. Code §65852.2 and §65852.22). Single-family parcels may have one ADU plus a Junior ADU when owner-occupied. Detached ADUs may reach 16 feet in height; attached units may reach 25 feet. Side and rear setbacks are 4 feet, and ADUs under 750 sq ft are exempt from impact fees.
View full Twain Harte rules →Key Facts Comparison
| Fact | Sonora | Twain Harte |
|---|---|---|
| Max Size | 1,200 sq ft detached | - |
| Height | 16 ft detached, 25 ft attached | - |
| Setbacks | 4 ft side/rear | - |
| STR Use | Prohibited (Ch. 17.64) | - |
| State Law | CA Gov Code §65852.2 | - |
| Permit Timeline | 60 days max | - |
| Local Ordinance | - | Tuolumne County Code Ch. 17.36 |
| State Preemption | - | Cal. Gov. Code §65852.2 / §65852.22 |
| Detached Height | - | 16 feet maximum |
| Attached Height | - | 25 feet maximum |
| Side/Rear Setback | - | 4 feet (new construction) |
| Impact Fee Exemption | - | ADUs under 750 sq ft |
| JADU Size | - | 500 sq ft max (owner-occupied) |
| Approval Timeline | - | 60 days (ministerial) |
Highlighted rows indicate differences between cities.
Sonora FAQ
Can I build an ADU in Sonora?
Yes. California law requires all cities to allow ADUs. Detached ADUs up to 1,200 square feet are permitted with 4-foot side and rear setbacks.
Can I rent my ADU as a short-term rental in Sonora?
No. Chapter 17.64 explicitly prohibits ADUs from being used as short-term rentals. ADUs must be rented for terms longer than 30 days.
How long does the ADU permit process take in Sonora?
State law requires permit review to be completed within 60 days. Contact Community Development at 209-532-3508 to apply.
Twain Harte FAQ
Can I build an ADU on my Twain Harte property?
Yes. Twain Harte is unincorporated Tuolumne County, and Chapter 17.36 of the County Ordinance Code allows one ADU on any single-family parcel, plus a Junior ADU if you live on the property. State law (Gov. Code §65852.2) prevents the County from banning them outright.
Do I need parking for my Twain Harte ADU?
Generally one space per bedroom, but under Gov. Code §65852.2 the requirement is waived if the parcel is within a half-mile walking distance of a public transit stop. You also do not have to replace parking lost when converting a garage to an ADU.
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