Walnut Creek ADU Standards
Prefab ADU in Walnut Creek
What is an Accessory Dwelling Unit (ADU)?
An ADU is an independent residential unit located on the same lot as a primary home. It provides additional living space, rental opportunities, or multi-generational housing. A prefab ADU is a permanent, factory-built backyard home that complies with local zoning and building codes, making it ideal for long-term living.
Tiny homes, often confused with prefab ADUs, are small, mobile units built on wheels. While both can serve as ADUs, prefab ADUs are stationary and built to last, whereas tiny homes face more zoning challenges due to their mobility.
Planning to Build an ADU in Walnut Creek?
With the implementation of updated ADU regulations, Walnut Creek has seen a rise in accessory dwelling unit construction. If you’re planning to build an ADU in Walnut Creek, LiveLarge is here to guide you through key development requirements to ensure a smooth and successful project.
Types of ADUs:
- Detached: A newly constructed unit built separately from the primary structure
- Attached: A newly constructed unit physically connected to the primary structure
- Conversion: A unit created by converting existing space within a primary residence or detached accessory structure
- Junior Accessory Dwelling Unit (JADU): A unit of up to 500 square feet created entirely within an existing single-family residence
Zoning and Lot Size
ADUs are permitted in all single-family residential, multi-family residential, and mixed-use zoning districts. JADUs are permitted in all single-family residential zones, as well as in multi-family zones that allow single-family dwellings. On a single-family zoned property, you can typically build one conversion or new attached ADU, one detached ADU, and one JADU.
Note: Certain exceptions may apply. For more information, refer to Section 10-2.3.503 of the ADU ordinance.
Size and Floor Area
Attached ADU:
Lots ≤ 14,999 sf: 850 sf (1-bedroom) or 1,000 sf (2+ bedrooms)
Lots 15,000–19,999 sf: 900 sf (1-bedroom) or 1,000 sf (2+ bedrooms)
Lots ≥ 20,000 sf: 950 sf (1-bedroom) or 1,000 sf (2+ bedrooms)
Statewide Exemption: 800 sf
If the unit exceeds 800 sf, its total gross floor area must not exceed 50% of the existing single-family dwelling’s gross floor area
Detached ADU:
Same square footage limits as above
Statewide Exemption: 800 sf
JADU (Junior ADU):
Maximum area: 500 sf
Setbacks and Height
- Attached ADU:
- Setbacks: 4-foot side and rear setbacks
- Height: 25 feet, or the maximum building height allowed for the primary dwelling, whichever is lower (up to 2 stories)
- Detached ADU:
- Setbacks: 4-foot side/rear; 5-foot from primary residence; 20-foot front setback
- Height: 16 feet
- Conversion of Existing Space:
- No setbacks are required for conversions of existing living areas or for structures reconstructed in the same location and to the same dimensions as the original
- JADU:
- Setbacks: 4-foot side/rear setbacks
Parking Requirements
- No additional parking spaces are required for ADUs or JADUs.
For more information, contact the Walnut Creek Planning Division at (925) 256-3558 or email DutyPlanner@walnut-creek.org.
Why Choose LiveLarge for Your ADU?
LiveLarge Prefab ADUs are designed to comply with Walnut Creek’s detached ADU regulations, offering a hassle-free way to enhance your property’s value. With pre-approved designs and expert guidance, we streamline the approval process.
Let LiveLarge be your trusted partner in your ADU journey. With our expertise in design, construction, and local compliance, we’ll ensure your project meets regulations and maximizes your property’s potential. Contact us today to get started!
Get A Free Site Report
Get A Free Site Report
