OneStop ADU: Your Accessory Dwelling Unit Builder in San Diego County
OneStop ADU is a full-service ADU contractor and accessory dwelling unit builder based in San Diego County. Whether the goal is to create a living space for aging parents, grown children, or to generate rental income from an investment property, OneStop ADU brings the expertise and experience needed to make it happen. Their in-house licensed building team has over 25 years of experience constructing homes and multi-family buildings throughout the San Diego area.
As a true detached ADU builder and general contractor, OneStop ADU does not rely on third parties or sell prefabricated units. Every structure is built using traditional construction methods, ensuring quality and longevity. They offer six pre-designed floor plans in three distinct exterior styles — Contemporary, Craftsman, and Spanish/Mediterranean — each with curated interior and exterior finish selections that create a cohesive designer look.
Because plans are already created, clients save time and money by avoiding the lengthy back-and-forth design process. Permit applications can also be submitted to the city more quickly, streamlining the entire journey from concept to completion.
What's Included in Their ADU Construction Pricing
OneStop ADU's construction pricing is designed to be transparent and comprehensive. Their pricing includes:
- Architectural and structural plans
- Title 24 report
- Permit processing
- Individually metered electrical upgrade (SDG&E fees not included)
- Required solar installation based on Climate Zone 7 requirements
Unlike many others in the industry, OneStop ADU includes the cost of solar power in their construction pricing. Per updated guidance from the California Department of Housing and Community Development (HCD), solar is required for all newly built, non-manufactured detached ADUs under Title 24. Panels may be installed on the ADU itself or on the primary dwelling unit.
Depending on the plan and finishes selected, total costs including design, permitting, and construction start at approximately $335 per square foot. Pricing is subject to change due to material and labor cost volatility.
OneStop ADU also offers ADA-compliant accessory dwelling units, crafted with flexible design options to meet the specific needs of individuals with disabilities.
Understanding ADU Eligibility and Regulations in California
Before any project begins, OneStop ADU conducts a free initial feasibility study of the client's San Diego County property. This no-cost, no-obligation consultation verifies all applicable local and state rules, confirms allowable sizes, and suggests general placement for the new structure.
Key regulatory points to be aware of include:
- California law allows a maximum 1,200 sq ft detached casita with a 16-foot height limit without local discretionary approvals
- There is no minimum lot size required for an ADU under California state code
- Even if a property's Floor Area Ratio is maxed out, an 800 sq ft granny flat with a 16-foot height limit and 4-foot setbacks is still permitted
- Per AB670, HOAs and CC&Rs cannot prohibit the construction of a granny flat on single-family zoned lots
- New ADU structures are assessed at market value but will not trigger reassessment of the existing primary home
City fees vary and may include impact fees, sewer connection fees, and school fees. Impact fees are waived for backyard cottages under 750 sq ft, and the City of San Diego currently waives all impact fees regardless of building size.
For clients interested in renting out their new granny flat or casita, OneStop ADU can provide a market study estimating potential gross rental income. Through their sister company, Onyx Property Management — with over 20 years of property management experience — they can also assist with tenant screening, rental rate optimization, and ongoing property maintenance.
