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An ADU (Accessory Dwelling Unit) is a fully independent living unit — either detached or attached — with its own kitchen, bathroom, and entrance. ADUs can be up to 1,200 square feet in San Diego. A JADU (Junior ADU) is a smaller unit (up to 500 sq ft) created by converting existing space within the primary home. JADUs require only an efficiency kitchen (no gas range) and may share a bathroom with the main house. The key advantage is that California law allows you to build both an ADU and a JADU on a single-family lot.

ADU construction costs in San Diego typically range from $150,000 to $375,000 for a detached unit, depending on size and finishes. Garage conversions are more affordable at $100,000–$175,000, while Junior ADUs can cost $50,000–$120,000. CRS Builders' design-build pricing includes everything — architectural plans, permits, engineering, construction, and final inspection. Get a personalized estimate with our ADU cost calculator.

Yes, you need stamped architectural plans to pull a building permit for an ADU in San Diego. However, with CRS Builders' design-build approach, architectural design is included in our service — no need to hire a separate architect. We handle the full design process in-house, including 3D renderings, structural engineering, and Title 24 energy calculations. You can also choose from our 10 pre-designed floor plans to save time and design costs.

ADUs in San Diego provide exceptional ROI. On average, a completed ADU adds $200,000–$350,000 in property value — often exceeding the construction cost. Monthly rental income averages $2,000–$3,500 depending on size and location, meaning most ADUs pay for themselves within 6–8 years. Read our detailed ADU rental income case study for real numbers from a completed project.

Under current California law (AB 68 and SB 9), single-family lots can have one ADU plus one JADU. Multi-family properties can add up to two detached ADUs. Some lots may qualify for additional units through SB 9 lot splits. The number of ADUs you can build depends on your lot size, zoning, and local regulations. Contact us for a free consultation to evaluate your specific property.

Yes, but only on the added value of the ADU — not your entire property. Under Proposition 13, your existing home's assessed value remains unchanged. Only the new construction (the ADU itself) is reassessed at current market rates. For a typical $250,000 ADU, you can expect an annual property tax increase of approximately $2,500–$3,000. This is typically offset many times over by rental income of $24,000–$42,000 per year.

Yes, but hillside lots may require additional engineering, grading, and retaining walls, which can increase costs. San Diego's hillside development regulations may also dictate setbacks and height restrictions. CRS Builders has experience building ADUs on challenging sites across La Jolla, Del Mar, and Point Loma — areas known for steep topography.

No. All ADU construction in San Diego requires a building permit — regardless of size. Unpermitted units cannot be legally rented, insured, or counted toward your property value. They also create serious liability issues. CRS Builders handles the entire ADU permitting process on your behalf, including plan submissions, city reviews, and final inspections.

Prefab ADUs may seem faster, but they often come with hidden costs — site preparation, foundation work, utility connections, and permits are rarely included. CRS Builders constructs every ADU on-site using traditional building methods, giving you far greater flexibility in design, materials, and finishes. Our builds are custom-tailored to your lot's unique conditions, and our design-build model means one team handles everything from blueprints to the final walk-through. No miscommunication between separate companies.