ADU Builder in Los Altos, CA
Los Altos is one of Silicon Valley’s most desirable neighborhoods, and one of the most lucrative markets for Accessory Dwelling Unit (ADU) investment. Apex Homes builds detached backyard cottages, attached in-law suites, and Junior ADUs throughout Los Altos, handling everything from zoning verification and permit drawings to construction and final sign-off. Average build time from permit approval: five months.
Los Altos ADU Regulations
Los Altos allows ADUs on both single-family and multi-family lots under California’s state ADU law. Key rules:
Single-Family (R-1) Lots
- Units: 1 detached or attached ADU + 1 JADU
- Size: Detached/attached up to 1,200 sq ft (attached also capped at 50% of main home); JADU up to 500 sq ft
- Setbacks: 4 ft from side and rear property lines
- Height: Detached up to 18 ft; attached up to 16 ft
- Separation: Minimum 5 ft between detached ADU and main house
Multi-Family Lots
- Units: Up to 2 detached ADUs; attached conversions up to 25% of existing units
- Size: Same limits as single-family (1,200 sq ft detached/attached; 500 sq ft JADU)
- Setbacks: 4 ft side and rear
- Height: Detached 18 ft; attached 16 ft
Apex Homes handles zoning verification, setback calculations, and lot coverage checks for every Los Altos project, so you don’t have to navigate city rules alone.
Build Your ADU in Los Altos
Start with ParcelZ. Check your property’s ADU eligibility in 60 seconds, for free. Then our team takes it from there.
Los Altos ADU Permitting Process
Los Altos follows California’s ministerial (non-discretionary) ADU approval pathway, which limits city review to 60 days by state law.
Confirm Eligibility
Verify your lot size, zoning designation, setbacks, and lot coverage allowance. Apex Homes runs this check for you at no cost.
Select Your Floor Plan
Choose from Apex Homes’ ADU floor plans: studio, 1-bedroom, and 2-bedroom options sized to fit your lot and budget.
Prepare Permit Documents
Required submittals typically include: site plan, utility layout, boundary survey, and architectural drawings. Apex Homes prepares the full permit package.
Submit to Los Altos Building Department
Applications are submitted directly to the City of Los Altos Community Development Department. The city must respond within 60 days under state law.
Construction & Inspections
Once approved, Apex Homes manages the full build: foundation, framing, MEP rough-in, inspections, and final certificate of occupancy.
Why Build An ADU in Los Altos?
Los Altos is one of Silicon Valley’s most desirable residential communities, and building an ADU here offers multiple benefits. ADUs can boost property values by 25-35% while also generating reliable rental income in a high-demand housing market. Beyond financial advantages, they provide living arrangements, making them ideal for guests who need privacy and comfort. At the community level, ADUs contribute to the local housing supply, foster neighborhood diversity, and make efficient use of existing lots without requiring new infrastructure.
Have questions? Contact Apex Homes Today
Our team knows Los Altos’ zoning, permits, and pricing inside out. Call us for a free, no-pressure conversation about your property. We’ll tell you exactly what’s possible.