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How Much Does an ADU Cost in the South Bay Area?

Written by Heartwood Team | Oct. 16, 2024

Accessory Dwelling Units (ADUs) have become popular in California, driven by housing demand and supportive legislation. However, the pressing question of how much an ADU costs in the South Bay Area still remains. If you're considering adding an ADU to your property in the South Bay Area, understanding the costs involved is a crucial step in the planning process. In this blog, we’ll explore the factors influencing ADU costs, how much you can expect to pay, and how legislation like AB 68 has simplified the process.

How Much Does an ADU Cost in San Jose, CA?

The cost of building an ADU in San Jose, CA, can vary widely depending on several factors, including the size of the unit, the quality of materials, and the project's complexity. On average, homeowners can expect to spend between $400K to $750K for an attached ADU. A detached ADU in the South Bay Area can range from  $500K to $1.25M, depending on various factors.

Factors Influencing the Average Cost of an ADU

Multiple factors can influence the cost of an ADU in the South Bay area, including size, material selection, proximity to utilities (mainly sewer), separate vs. shared meters, 1 vs. 2 stories, and soil type (when building a detached ADU). We'll dig deeper and explain how you can work with some of these factors and how some are immutable. 

Size and Design Complexity

The size of the ADU, whether a studio, one-bedroom, or two-bedroom unit, significantly impacts the overall cost. Larger units with more complex designs will naturally cost more.

Material Quality

You want your ADU to be beautiful and built with the best materials. Much like a home, high-end finishes, custom cabinetry, and premium appliances will increase the overall cost. 

Labor Costs

Labor costs in San Jose are generally higher than in other parts of California, contributing to the overall expense. Skilled subcontractors and, of course, a skilled builder are vital parts of your ADU investment.

 

How Much Does It Cost to Build Per Square Foot in the South Bay Area?

In the South Bay Area, the cost to build an attached ADU per square foot typically ranges from $800 to $1,000, and the average price of a detached ADU ranges from $1,000 to $1,250 per square foot. This range accounts for the construction methods, materials, and finishes used.

Factors Affecting Cost Per Square Foot

  • Quality of Materials

  • Labor Rates

  • Site Conditions

  • Design Complexity

How Much Is a 2-Bedroom ADU in California?

A two-bedroom ADU is a popular choice for homeowners looking to maximize living space. In San Jose, the cost of building a two-bedroom ADU typically ranges between $500K and $750K for an attached ADU and $700K to 1.2 million for an unattached ADU, depending on the factors mentioned earlier.

At Heartwood Residential, we appreciate the investment you're making by choosing us to build your ADU and work hard to match your needs with your budget. We understand the balance of space, budget, and needs when building any structure and strive to strike the perfect balance of those factors for you with our ADU services.

Additional Costs to Consider

  • Site Preparation
  • Utilities
  • Landscaping

How AB 68 Revolutionized ADU Building in California

The introduction of AB 68 in 2019 was a game-changer for ADU construction across California. This legislation aimed to address the state's housing crisis by making it easier and faster to build ADUs. We've summarized how AB 68 has impacted the ADU building process.

Streamlined Permitting Process

AB 68 mandates that local governments approve or deny ADU permit applications within 60 days, significantly speeding up the process. Before this, the permitting process could take several months or even longer, causing delays and increased costs for homeowners.

Relaxed Zoning Restrictions

AB 68 also eased zoning restrictions, allowing more homeowners to qualify for ADU construction. It reduced setback requirements and allowed for the construction of ADUs on properties that previously wouldn’t have qualified, such as those with limited space or unconventional lot shapes.

Multiple ADUs Allowed

The bill allows homeowners to build both an attached and a detached ADU on the same property, as well as a junior ADU (JADU) within the primary residence. This change has allowed homeowners to significantly increase the living space on their property, providing more housing options for renters and family members.

Reduced or Waived Impact Fees

Impact fees are either reduced or waived for ADUs under 750 square feet. This has made smaller ADUs, like studios and one-bedroom units, more affordable, further incentivizing homeowners like you to invest in them.

 

What Is the Cheapest Way to Build an ADU in California?

Choosing a team of professionals will also be a higher investment than building an ADU via DIY. But no matter your budget, everyone wants to be savvy with their money. Let's discuss a few ways to keep your investment on the right track. 

Choosing the right ADU Builders in the South Bay Area

If you're investing in an ADU builder in the South Bay Area rather than attempting a DIY project, it's because you understand the value and quality that comes from hiring professionals for this type of project. However, the wrong builder can make costly mistakes that greatly impact the cost of building an ADU. Heartwood Residential brings experience, knowledge, and a commitment to superior work to every project. 

Choosing a Smaller ADU 

Understandably, even if a 400-square-foot ADU costs the same per square foot as a 1,000-square-foot structure, the cost of the 400-square-foot ADU will be less than the larger one. Depending on what you're using the structure for, a smaller ADU will work just as well for your needs.

Simplified Design

In line with the previous points, high-quality workmanship doesn't have to mean the most elaborate designs, especially if those designs don't match your goals. Don't artificially inflate the cost of your ADU in San Jose with features or floors you don't want or need.

 

Your South Bay Area ADU Builder

Building an ADU in the South Bay Area is a significant investment you don't make lightly. If you're considering the costs of building an ADU, you've realized that your household needs one. Now is a fantastic time to invest in an ADU, thanks to AB 68.

Heartwood Residential is here to help you build an ADU, elucidate the process, and make you comfortable every step of the way. Don't settle for a builder who doesn't value your investment, and understand what adding an ADU to your home means to your family.

Contact Us

Contact us today to begin the process of building an ADU on your property. We're here to serve you!