How Much Does an ADU Cost in Los Gatos? (2026)

Los Gatos is a town that takes its design standards seriously. Whether you're on a historic street in Almond Grove, near the Monte Sereno border in the western hills, or in a Blossom Hill neighborhood subdivision, any accessory dwelling unit here needs to fit the character of the surrounding homes. That's a good thing — it's part of what makes Los Gatos Los Gatos — but it also shapes what an ADU costs and how the approval process goes.

This guide covers ADU cost in Los Gatos for 2026, broken down by type, with honest ranges and the local context you need to plan intelligently.

Silicon Valley Kitchen & Bath Co. has been building ADUs across Santa Clara County and the greater Bay Area since 2012. CSLB #975092.

ADU Types and 2026 Cost Ranges in Los Gatos

ADU Type	Description	Typical Cost Range
Garage Conversion (JADU / ADU)	Convert attached or detached garage into living space	$120,000 – $200,000
Attached ADU	Addition to existing home structure, with separate entrance	$200,000 – $350,000
Detached New Construction	Standalone structure on existing lot	$250,000 – $450,000+

Per-square-foot cost typically runs $400–$650 for new detached construction in Los Gatos. That range shifts toward the higher end for hillside lots, custom architectural detailing required to match historic homes, or premium finish specifications. Costs vary by scope and site conditions — these are planning estimates, not fixed bids.

What Makes Los Gatos ADU Projects Distinct

Design review. Los Gatos requires ADUs to be architecturally compatible with the primary residence and the neighborhood. This means roofline, material palette, window proportions, and exterior finish all get reviewed. Plan on architectural drawings that meet this standard — a cut-sheet spec package won't get through. This adds cost but also protects the investment value.

Hillside lots. Properties near the Monte Sereno border and in the western hills often sit on sloped terrain. Grading, retaining walls, and engineered foundations add to the base build cost. We typically see $20,000–$60,000 in site work added to hillside ADU projects, depending on grade and soil conditions.

Historic Almond Grove. The Almond Grove Historic District has additional review requirements for visible changes to properties. An ADU here needs to be sensitive to the streetscape — detached backyard structures are generally more feasible than front-facing additions.

Utility connections. Los Gatos requires separate utility connections for ADUs in most cases. Water and sewer connection fees through San Jose Water or the town's public works vary but can add $5,000–$20,000 to project costs.

Garage Conversions: The Fastest Path

Garage conversions are popular in Los Gatos because state law (AB 2221/SB 897) streamlines permitting for garage-to-ADU conversions. You're working within an existing structure, which avoids foundation costs and can reduce permit review time.

A typical 400–500 sq ft garage conversion in Los Gatos runs $120,000–$175,000. That gets you insulation, drywall, flooring, a kitchenette, full bathroom, mini-split HVAC, electrical service upgrade, and windows to meet egress requirements. Higher-end finishes — custom tile, Hansgrohe fixtures, stone counters — push toward $175,000–$200,000.

One watch-out: older garages may have substandard concrete slabs that need repair or leveling before finishing. Our pre-construction assessment flags this before you're surprised mid-build.

Detached ADUs: Maximum Flexibility

A detached new-build ADU gives you the most design freedom. You can size it appropriately for the lot (Los Gatos allows up to 1,200 sq ft for detached ADUs under state law), design it to maximize natural light, and specify finishes that reflect the quality of the primary residence.

For a 600–800 sq ft detached ADU in Los Gatos, expect $280,000–$380,000. A 1,000+ sq ft unit with premium finishes can reach $400,000–$450,000+. These figures include architectural design, permitting, foundation, framing, roofing, all MEP (mechanical, electrical, plumbing), finishes, and landscaping restoration around the new structure.

Our ADU services in Los Gatos cover the full scope from design through final inspection — one team, one contract, one accountable point of contact.

Permits and Timeline in Los Gatos

The Town of Los Gatos Community Development Department handles ADU permits. The town participates in the state's streamlined ADU permitting (ministerial approval for qualifying projects), which means the town must act within 60 days of a complete application for most ADU types.

Typical total timeline:

• Architectural design and permit application: 6–10 weeks
• Town plan check review: 4–8 weeks (ministerial streamlining helps here)
• Construction: 12–24 weeks depending on type
• Total project: roughly 6–12 months from kickoff to certificate of occupancy

Financing and Return

ADUs in Los Gatos generate meaningful rental income — Los Gatos rents are among the highest in Santa Clara County. A well-finished 600 sq ft ADU might rent for $3,200–$4,200/month, which changes the ROI math significantly compared to treating it purely as a construction expense.

Common financing paths: home equity line of credit (HELOC), cash-out refinance, or construction loan. California's ADU grant programs have been popular but fluctuate in availability; check with your lender on current options.

Our ADU services page covers the full process. We also recommend reading our free planning guides before you start comparing bids — they help you ask the right questions.

Frequently Asked Questions

Can I build an ADU anywhere in Los Gatos?

Most Los Gatos properties can accommodate some form of ADU under current state law, but site-specific factors matter: lot size, setbacks, existing structures, slope, and whether the property is in a historic overlay zone. Properties in the Almond Grove Historic District have additional review. Our site assessment determines feasibility before you commit to a full design process.

How does Los Gatos compare to San Jose or Campbell for ADU permitting?

Los Gatos is generally more thorough in its design review than larger cities. The upside is that ADUs here tend to be higher quality and better integrated with their surroundings. The process takes slightly longer than streamlined programs in larger jurisdictions, but the town has been cooperative with state ADU law requirements.

What size ADU can I build in Los Gatos?

State law allows detached ADUs up to 1,200 sq ft regardless of lot size (for most residential zones). JADUs (junior ADUs) are capped at 500 sq ft and must be within the existing primary dwelling. Setback requirements apply: generally 4 feet from rear and side property lines for detached ADUs under the state standard.

Let's Plan Your Los Gatos ADU

An ADU in Los Gatos is a significant investment — and when it's designed well, it adds lasting value to properties that already command premium prices. Our team knows the town's review process and the quality expectations that come with building here.

Get in touch for a free consultation and let's walk through what's possible on your lot.

Related reading:

• How Much Does a Kitchen Remodel Cost in Los Gatos? (2026)
• How Much Does a Bathroom Remodel Cost in Los Gatos? (2026)

Silicon Valley Kitchen & Bath Co. · (408) 903-3390 · CSLB #975092 · Licensed since 2012 · Serving homes across Los Gatos and the Bay Area from Napa to Carmel.