Custom ADU Backing up to the Santa Fe Valley Preserve
San Antonio Rose Court, San Diego, CA 92127
Homeowner Story: Generate rental income
Special Circumstance: HOA
Highly Custom ADU in the Crosby Estates Rancho Santa Fe HOA
This custom 3-bedroom, 2-bathroom ADU in San Diego was designed within the strict architectural requirements of the Crosby Estates at Rancho Santa Fe HOA. The irregular floor plan was shaped directly by existing retaining walls, and site condition constraints, and homeowner preferences resulting in a highly customized layout that maximizes the available space while maintaining privacy and views toward the Santa Fe Valley Preserve.
The 1,200 sqft design features an angled footprint that creates separation between the living areas and bedrooms. The open-concept living room and kitchen anchor one side of the home, while the bedrooms are positioned along the extended wing of the structure. Large windows throughout the ADU take advantage of the surrounding natural setting and bring additional light into the interior spaces.
Because of the retaining walls near the site, portions of the foundation required deepened footings to accommodate the layout safely and efficiently. The result is a one-of-a-kind ADU designed specifically for the property rather than a standard rectangular floor plan, creating a flexible rental opportunity within one of Rancho Santa Fe’s most regulated communities.
Learn more about building an ADU in an HOA.
Floor Plan:
Custom ADU Floor Plan
Community:
The County of San Diego Accessory Dwelling Unit Guide
The County of San Diego oversees ADU development throughout the region’s unincorporated communities, including areas such as Rancho Santa Fe, Valley Center, Bonsall, Fallbrook, Lakeside, Spring Valley, and many others. You may also think your property is in a certain jurisdiction because your address includes a city, such as Escondido, but you actually fall outside of city limits and are within the county jurisdiction. Understanding which jurisdiction applies is one of the first steps in determining what can be built.
The County allows a variety of ADU configurations, including two-story ADUs and guest quarters in addition to an ADU. In 2026, the County also became one of the first jurisdictions in San Diego County to adopt AB1033, allowing qualifying ADUs to be sold separately from the primary residence. As of June 2026, only the County of San Diego and the City of San Diego have adopted AB1033.
Unlike many jurisdictions, the County still requires in-person permit submissions, which can add some time and coordination during the permitting process. Depending on the location of the property, other agencies such as local fire districts may also require review and approval before permits can be issued.
San Diego County ADU Permitting
Most ADU permits within the County of San Diego are approved within approximately 3 to 5 months after submission, although timelines vary depending on project complexity and agency review requirements. Compared to some cities within San Diego County, permit fees are generally moderate. ADU permit costs often range from approximately $15-$18 per square foot, depending on the size and scope of the project.
The County requires in-person permit submissions and, depending on the property’s location, additional review from agencies such as local fire districts. Early planning can help identify these requirements and create a more predictable permitting process.
Unlike many coastal cities in the region, only a small portion of the County’s jurisdiction falls within the Coastal Zone. Most County ADU projects therefore do not require Coastal Zone review.
