What building codes apply to ADUs in San Jose?

Hello,

Thank you for reaching out with your questions about building an Accessory Dwelling Unit (ADU) in San Jose. You're right; San Jose is indeed supportive of ADU development, and with your lot size and budget, you have a good foundation to start this project. Let’s dive into the specifics to help you navigate this process smoothly.

### Building Codes and Regulations

**1. Setback Requirements:**
In San Jose, the setback requirements for ADUs typically depend on whether the unit is attached or detached:
- **Detached ADUs:** Generally require rear and side setbacks of at least 4 feet. Front yard setbacks usually align with existing zoning regulations, typically ranging from 20 to 25 feet.
- **Attached ADUs:** Must comply with the existing side and rear setbacks of the primary residence, which may vary based on your zoning district.

**2. Height Restrictions:**
- For detached ADUs, the maximum height is typically 16 feet, though this can be extended up to 18 feet in some cases to accommodate roof pitches similar to the primary residence.
- Attached ADUs adhere to the height limitations of the primary dwelling or applicable zoning regulations.

**3. Lot Coverage and Size Limits:**
- You can generally build an ADU up to 1,000 square feet on your property; however, this may be influenced by your lot's zoning and existing structures.
- There's no minimum lot size requirement for building an ADU, thanks to California’s AB-68, which removed such restrictions to simplify the creation of ADUs.

**4. Different Rules for Attached vs. Detached:**
- Yes, there are distinctions. Detached ADUs typically have more flexible setback requirements but are more limited in size compared to attached ADUs, which can be up to 50% of the primary residence's size.

### Permitting Process and Costs

**1. Permits and Fees:**
- The permitting process in San Jose can take anywhere from 2 to 6 months, depending on the complexity of your project and the current workload at the city's planning department.
- Expect to pay permit fees, which can range from $5,000 to $15,000, including building, planning, and impact fees. San Jose has waived certain fees for ADUs under 750 square feet, which can be a cost-saving advantage.

**2. Hidden Costs:**
- Utility connections are often an overlooked expense. If your ADU requires new or upgraded water, sewer, or electrical connections, these costs can add several thousand dollars to your budget.
- Consider soft costs such as design and engineering fees, which can add another $10,000 to $20,000.

### Regulations to Consider

- **California State Laws:** SB-9 offers more flexibility in constructing additional units, allowing for easier lot splits and simplified permitting processes. AB-68 reduces barriers like parking requirements and minimum lot sizes.
- **Local Ordinances:** San Jose has its own ADU Ordinance, which aligns with state laws while offering specific guidelines to streamline approvals, especially in residential zones.

### Tips and Common Pitfalls

- **Hire Experienced Professionals:** Work with architects or builders familiar with San Jose’s ADU processes. They can help expedite your project by ensuring plans meet local standards.
- **Be Thorough with Planning:** Overlooked zoning details or misinterpreted building codes can lead to costly revisions. Double-check everything.
- **Consider Pre-Approved Plans:** San Jose offers pre-approved ADU plans which can save you time and money in the design phase.

### Next Steps

1. **Consult with the San Jose Planning Department:** They offer preliminary review services which can provide insights into potential challenges or adjustments needed for your project.
2. **Explore Financing Options:** Look into local rebates or financing programs that might help offset costs, such as low-interest loans or grants for ADU construction.
3. **Join Local ADU Workshops:** These can provide valuable insights and connect you with other homeowners and professionals.

For further guidance, check out the City of San Jose’s website and the resources offered by the California Department of Housing and Community Development. Engaging with local ADU networks or forums can also provide firsthand experiences from fellow homeowners.

Building an ADU is a substantial investment, but with careful planning and adherence to local regulations, it can significantly enhance your property's value and utility. Best of luck with your project!

Warm regards,

[Your Name]
ADU Expert & Consultant