ADU Construction in Atherton
Atherton 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 Atherton with full 3D visualization and itemized pricing through our two-phase process.
How much does an ADU cost in Atherton?
Atherton 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 Atherton is a Strong Market for ADU Construction
Atherton’s 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. Established neighborhoods and proximity to both San Francisco and Silicon Valley create consistent demand for quality construction.
Custom Home builds ADUs in Atherton 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 Atherton
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 Atherton 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 Atherton, starting from $250K. Since the structure already exists, you save on foundation, framing, and roofing costs.
Atherton ADU Permitting
Atherton’s Building Division reviews all residential construction applications with particular attention to tree preservation, setbacks, and neighborhood character. Plan review for custom homes typically takes 6-10 weeks. Heritage tree removal requires a separate permit and arborist report. The town’s design review process applies to all new construction and significant exterior modifications.
Custom Home manages the entire ADU permitting process in Atherton, preparing plans that meet local requirements for efficient review and approval.
ADU Rental Income Potential in Atherton
Atherton’s 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 Atherton
Atherton 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 $700-$1000/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.
Atherton Permit Requirements
Atherton's Building Division reviews all residential construction applications with particular attention to tree preservation, setbacks, and neighborhood character. Plan review for custom homes typically takes 6-10 weeks. Heritage tree removal requires a separate permit and arborist report. The town's design review process applies to all new construction and significant exterior modifications. Custom Home handles the entire ADU permitting process, preparing plans that meet local requirements for efficient approval.
ADU Construction in Atherton: FAQ
What does ADU construction cost in Atherton?
ADU costs in Atherton 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 Atherton?
ADU construction in Atherton 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.
Can I rent out my ADU in Atherton?
Yes. California law allows ADU rentals, and Atherton does not require owner-occupancy. Many homeowners earn $3,500-$5,500/month in rental income from their ADU, making it a strong investment.