ADU Construction in Los Altos Hills
Los Altos Hills is a strong market for ADU construction, with options ranging from $250K for a garage conversion to $800K+ for a large detached unit. Custom Home builds detached, attached, and garage conversion ADUs in Los Altos Hills with full 3D visualization and itemized pricing through our two-phase process.
How much does an ADU cost in Los Altos Hills?
Los Altos Hills ADU costs range from $250K-$400K for a garage conversion to $450K-$800K for a detached unit in 2026. Custom Home's two-phase process provides 3D visualization and exact pricing before construction begins.
Why Los Altos Hills is a Strong Market for ADU Construction
Los Altos Hills’ large lots and high property values make ADU construction a compelling investment. A well-designed guest house or detached studio adds both functionality and value to estate-level properties. Silicon Valley’s tech-driven economy supports strong demand for modern, energy-efficient residences.
Custom Home builds ADUs in Los Altos Hills with the same two-phase design-build process we use for custom homes. You see the complete design in 3D and receive itemized pricing before any construction begins.
Types of ADUs We Build in Los Altos Hills
Detached ADUs
A standalone structure in your backyard, typically 400-1,200 sqft. Detached ADUs offer the most privacy and design flexibility. They work well for rental units, home offices, or multigenerational living. Construction costs in Los Altos Hills typically range from $450K to $800K.
Attached ADUs
Built as an addition to your existing home, sharing at least one wall. Attached ADUs are typically more cost-effective than detached units since they share structural elements with the main house. They are a good fit for family members who want proximity while maintaining separate living spaces.
Garage Conversions
Converting an existing garage into a living space is the most affordable ADU option in Los Altos Hills, starting from $250K. Since the structure already exists, you save on foundation, framing, and roofing costs.
Los Altos Hills ADU Permitting
Los Altos Hills processes building permits through its Planning and Building Department. All new construction requires review by the Architectural and Site Control Commission, which evaluates design, grading, tree preservation, and compatibility with the town’s rural character. Plan review typically takes 6-10 weeks due to the additional environmental and site considerations.
Custom Home manages the entire ADU permitting process in Los Altos Hills, preparing plans that meet local requirements for efficient review and approval.
ADU Rental Income Potential in Los Altos Hills
Los Altos Hills’ rental market supports strong returns for ADU owners. Estimated monthly rental rates:
- Studio/1-bedroom (400-600 sqft): $3,500-$4,000/month
- 1-bedroom (600-800 sqft): $3,900-$5,200/month
- 2-bedroom (800-1,200 sqft): $5,000-$5,500/month
At these rates, many ADU investments pay for themselves within 7-12 years through rental income alone, not counting the property value increase that a permitted ADU provides.
Pricing for ADU Construction in Los Altos Hills
Los Altos Hills ADU construction costs range from $250K for a basic garage conversion to $800K+ for a large detached unit with premium finishes. Per-square-foot costs typically run $600-$900/sqft. Garage conversions are the most cost-effective option since the structure already exists. Custom Home provides itemized pricing during Phase 1 so you know every cost before committing.
Los Altos Hills Permit Requirements
Los Altos Hills processes building permits through its Planning and Building Department. All new construction requires review by the Architectural and Site Control Commission, which evaluates design, grading, tree preservation, and compatibility with the town's rural character. Plan review typically takes 6-10 weeks due to the additional environmental and site considerations. Custom Home handles the entire ADU permitting process, preparing plans that meet local requirements for efficient approval.
ADU Construction in Los Altos Hills: FAQ
What does ADU construction cost in Los Altos Hills?
ADU costs in Los Altos Hills range from $250K for a garage conversion to $800K+ for a large detached unit. The biggest cost factors are ADU type, size, finishes, and utility connections. Custom Home provides itemized pricing during Phase 1 so you know every cost upfront.
How long does it take to build an ADU in Los Altos Hills?
ADU construction in Los Altos Hills typically takes 6-12 months from design to move-in. Garage conversions are fastest at 4-6 months, while detached units take 8-12 months including permits. Custom Home's design phase front-loads decisions to keep construction on schedule.
Does Los Altos Hills offer pre-approved ADU plans?
Many Bay Area cities, including some in Santa Clara County, offer pre-approved ADU plans that can reduce permitting time. Custom Home can advise on whether pre-approved plans are available for your Los Altos Hills property or whether a custom design is the better option.