What happens if you skip the permit (and you needed one)
- Stop-work orders fine $500–$2,000 per violation in Los Gatos; city may require demolition of unpermitted work or conditional-use hearing to legalize it, costing $5,000–$10,000+ in consultant/attorney fees.
- Insurance claim denial: most homeowners policies exclude coverage for unpermitted work; if injury or fire occurs in the ADU, your claim is likely denied, exposing you to $100,000+ liability.
- Title and resale hit: unpermitted ADU must be disclosed as a structural modification under California Real Estate Transfer Disclosure Statement; most title companies will not insure the property until it is legalized, tanking resale value by 10–25%.
- Lender lock-out: refinancing or HELOC is blocked; loan servicers run title searches and flag unpermitted ADUs, forcing you to either legalize (expensive) or abandon the refinance.
Los Gatos ADU permits — the key details
California Government Code § 65852.2 (and the newer § 65852.22 for junior ADUs) mandates that local agencies 'shall ministerially approve' ADUs that meet objective design standards, zoning, and parking criteria. Los Gatos cannot reject an ADU application purely on 'character' or 'neighborhood compatibility' grounds, but it can enforce setback rules, lot-coverage limits, parking waivers, and utility requirements. The city's local ADU ordinance (updated to align with AB 671 and SB 9) sets objective standards: detached ADUs must maintain 5 feet from rear property line and 3 feet from side property lines (standard for the zoning district); garage conversions must preserve one off-street parking space (but this can be waived if on-street parking is available); junior ADUs (bedroom + kitchen carved out of the primary home) do not require additional parking. The key Los Gatos rule: if your ADU is on a lot in the Historic District overlay, you must submit to ADU Design Review (in addition to building permit), which means the Planning Commission reviews the unit's exterior color, materials, and massing for consistency with historic character. This adds 4–6 weeks and a $1,500–$2,500 planning consultant fee if you hire one.
Separate utility connections are required for detached ADUs and garage conversions; junior ADUs can share utilities with the primary home but must have a separately metered water supply. The City will not issue a certificate of occupancy until PG&E and the water utility confirm separate service (or sub-metering for junior ADUs). If your lot does not have adequate utility easements or if water/sewer lines must cross a neighbor's property, you may need a utility easement agreement, which can take 4–8 weeks and cost $2,000–$5,000 in title work and negotiation. Electrical: if the ADU is more than 200 amps, it may require a separate meter base; PG&E's interconnection process can add 6–12 weeks. Check PG&E's website and submit a service request early; the city will not sign off on the permit until PG&E confirms feasibility. Sewer: if your lot is on city sewer, the city's Public Works Department will review the lateral connection; if you're on a septic system, the ADU may trigger an upgraded system (soil testing, percolation test, $15,000–$30,000), and the Health Department must approve design.
Parking requirements in Los Gatos are not waived for detached ADUs under state law (unlike some Bay Area cities); however, the city's code (LGMC § 29.14.340) allows a parking requirement waiver if on-street parking is available and the lot is within a half-mile of frequent transit. Garage conversions must preserve one parking space (usually the driveway) or the applicant must submit a waiver request with evidence of on-street availability. Junior ADUs do not require additional parking. If your ADU is in downtown Los Gatos (near the Caltrain station) or near a frequent-transit corridor, parking waivers are routinely granted; elsewhere, expect to provide one off-street space. The city also enforces a 'primary residence occupancy' rule: the owner must occupy either the primary home or the ADU; you cannot rent out both. State law (AB 68, effective 2025) is softening this, but Los Gatos has not yet amended its code, so enforce compliance in your paperwork.
Setback and lot-coverage rules apply strictly in Los Gatos, especially in residential zones. Detached ADUs must meet the same setbacks as the primary home: typically 5 feet rear, 3 feet side, and 25 feet front (varies by zone). Junior ADUs are exempt from setback rules. Garage conversions that add square footage to the footprint (e.g., an overhang or extended roof) must comply with side setbacks. The city's zoning map includes several hillside overlay zones (San Jose foothills) where ADUs may be restricted based on slope and vegetation; if your lot has a slope exceeding 15%, you may need a geotechnical report. The Planning Department's website has a 'Zoning Lookup Tool' where you can check your lot's overlay; use it before hiring a designer.
Owner-builder is allowed under California B&P Code § 7044, which permits the owner to pull permits for improvements to their own residence (including ADUs). However, all electrical work must be done by a licensed electrician (or the owner if licensed in that trade), and all plumbing must be licensed as well. Los Gatos' building inspector will verify contractor license numbers on the application; if you list yourself as the electrician and you're not licensed, the permit will be flagged. The city does not offer over-the-counter ADU permits; all applications go to plan review (8–12 weeks typical), and the 60-day deemed-approved shot clock under AB 671 does not begin until the application is formally accepted. Once accepted, if the city does not respond to a completeness letter within 60 days, the project is deemed approved and you can begin construction (though you still need to schedule inspections). This is rare in practice because Los Gatos does issue completeness letters, which restart the 60-day clock.
Three Los Gatos accessory dwelling unit (adu) scenarios
State ADU law override and Los Gatos' local constraints
California Government Code § 65852.2 (primary ADU law) and § 65852.22 (junior ADU law, effective 2020) require local jurisdictions to 'ministerially approve' ADUs that meet objective design standards. 'Ministerially' means no discretionary review—if you meet the checklist, the city must approve it. Los Gatos cannot say 'no ADUs in this neighborhood' or 'this doesn't fit the character.' However, state law allows local agencies to impose objective standards on lot coverage, setbacks, parking, and height. Los Gatos has chosen to enforce these standards strictly, which means your ADU can be denied if it violates a setback or exceeds the lot-coverage cap, even though state law overrides the city's zoning prohibition on ADUs.
The city's ADU ordinance (LGMC § 29.14) cross-references state law and adds local objective standards: detached ADUs on a lot are limited to 40% of primary structure square footage (up to 1,200 sq ft), must meet a 5-foot rear setback, and must not exceed lot-coverage limits. Junior ADUs have no square-footage cap under state law and no setback requirement. Garage conversions must preserve or provide one parking space. The city also enforces an owner-occupancy rule (not yet amended post-AB 68), so verify that either you or a family member will occupy the primary home or ADU; you cannot rent both to tenants. This is a local constraint that state law has not fully preempted, though AB 68 may require Los Gatos to revise in 2025.
A Los Gatos-specific advantage: the city has posted example ADU plans on its Planning Department website (search 'Los Gatos ADU Templates'). If your lot matches one of these templates and you use the plan set, you can often skip one round of plan review and go directly to permit issuance, cutting 3–4 weeks off the timeline. These templates already incorporate Los Gatos setbacks, parking, and utility routing, so you're essentially pre-approved for design. If your lot or project scope differs materially, the template approach won't work, and you're back to the standard 8–12 week review cycle.
Utility infrastructure and PG&E interconnection — the hidden timeline risk
The single biggest delay in Los Gatos ADU projects is PG&E's electrical interconnection process. If your detached ADU requires a new meter or service upgrade (e.g., the existing service to the primary home is 100 amps and the new combined load is 200+ amps), PG&E must design and install new infrastructure. This can take 8–16 weeks from request to completion, and PG&E's timeline is often not coordinated with the city's building permit approval. A common sequence: you submit your ADU building permit application with a single-line electrical diagram; the city approves the permit in 10 weeks; you then submit a PG&E service request; PG&E takes another 12 weeks to complete the new meter installation; meanwhile, your building permit is sitting idle because you can't legally energize the ADU until PG&E's work is done. Smart developers request a PG&E preliminary feasibility letter before submitting the building permit, which shortens the overall timeline by identifying required upgrades upfront.
Water and sewer are equally critical. If your lot is on city water and sewer (most of Los Gatos is), the Public Works Department reviews the meter and lateral connections. Typical turnaround: 2–4 weeks, assuming the water line and sewer main are accessible. If your property is on a septic system (less common in town but possible in the hillside areas), a septic-system upgrade is often required; soil tests and design can take 4–8 weeks, and the Santa Clara County Health Department must approve. Budget $15,000–$30,000 for septic upgrades. Gas service (if desired) is usually straightforward (2–3 weeks), but if the meter location conflicts with setback rules or tree-preservation requirements, it can add delays.
Pro tip: before you hire an architect, contact PG&E, the city's Water Department, and (if on septic) the county Health Department for preliminary feasibility letters. These are free and take 2–4 weeks but can reveal fatal flaws (e.g., 'no service capacity available in your area') before you spend $8,000 on plans. Los Gatos' Planning Department can direct you to the right utility contacts; they often have relationships with PG&E's development team and can expedite a feasibility request.
Town of Los Gatos, 110 E Main Street, Los Gatos, CA 95030
Phone: (408) 399-5200 (main line; ask for Building or Planning) | https://www.losgatosca.gov/159/Building-Planning (check for online permit portal link on Planning Department page)
Monday–Friday, 8 AM–5 PM (call ahead to confirm walk-in hours; some departments have limited in-person availability)
Common questions
Can I build a junior ADU without a separate parking space?
Yes. Junior ADUs (one bedroom + kitchen carved out of the primary home) are exempt from additional parking requirements under California law (Government Code § 65852.22). You do not need to provide or reserve a separate parking space for the junior ADU. If your lot already has driveway parking for the primary home, that satisfies the requirement. Los Gatos enforces this exemption strictly.
What's the cheapest path to a Los Gatos ADU — junior ADU, garage conversion, or detached new build?
Junior ADU is cheapest: $25,000–$40,000 total (permits + construction), no setback requirements, no separate parking, 16–20 weeks. Garage conversion: $30,000–$50,000 total, fast if not in historic district (18–20 weeks), slow if historic (24–28 weeks due to design review). Detached new build: $50,000–$80,000+ total, longest timeline (20–24 weeks). Soft costs (permits + architecture) are $8,000–$15,000 regardless. Choose junior ADU if your primary home has the space; it is the regulatory and cost sweet spot.
Does Los Gatos allow an owner-builder to do the electrical work on an ADU?
Only if the owner is a licensed electrician (under California B&P Code § 7044). If you're not licensed, you must hire a licensed electrician; the city will verify license numbers on the permit application. Same rule applies to plumbing. Unlicensed owner-builders can do framing, drywall, and finish work but must subcontract the trades.
How long does the building permit approval really take in Los Gatos — is it really 60 days?
The state's 60-day deemed-approved shot clock (AB 671) applies, but Los Gatos' practice is 8–12 weeks in reality. The 60 days restarts with each completeness letter the city issues; if the city asks for revisions and you resubmit, the clock restarts. Most ADU projects go through 2–3 completeness cycles, so the true review time is 10–14 weeks from initial application to approval. Historic District design review (Scenario B) adds another 4–6 weeks. If you hit a geotechnical flag (Scenario C), plan for 14+ weeks.
Can I rent out both the primary home and the ADU in Los Gatos, or does one have to be owner-occupied?
Currently, Los Gatos enforces an owner-occupancy requirement: the owner must reside in either the primary home or the ADU (but not rent both to tenants). This is a local rule that is not yet preempted by state law. However, California AB 68 (effective January 2025) is expected to eliminate owner-occupancy requirements statewide; Los Gatos will likely amend its code to comply, but contact the Planning Department to confirm current status. If you plan to rent both units, ask the city in writing for a current interpretation before you commit.
What if my lot is in the Los Gatos Historic District overlay — does that block my ADU?
No, it does not block the ADU, but it adds ADU Design Review (4–6 weeks) on top of the building permit review. The Planning Commission reviews the ADU's exterior color, materials, window style, and massing to ensure compatibility with historic character. Budget an extra 4–6 weeks and hire a design architect familiar with historic guidelines ($2,000–$4,000) to increase approval odds. Design review is not a discretionary veto; if your design meets the Historic District Design Guidelines, it must be approved.
Is a geotechnical report really required for a hillside ADU in Los Gatos?
Yes, if your lot is in a Hillside Development overlay zone (common in the foothills and upper Los Gatos neighborhoods). A geotechnical site assessment (report, boring, soil analysis) is required to assess slope stability and oak-tree preservation. Cost: $3,000–$5,000. This report is submitted with your building permit application and is reviewed by the Planning Department's environmental staff. If the report flags slope failure risk or requires expensive retaining walls, the project may be denied or heavily conditioned. Check your zoning on the city's online zoning map before you hire an architect.
Can I use a pre-approved ADU plan template from Los Gatos to speed up my permit?
Yes, if your lot matches one of the city's example ADU plans posted on the Planning Department website. These templates are pre-reviewed and incorporate Los Gatos' setbacks, parking, and utility routing, so you can often skip a round of plan review (saving 3–4 weeks). However, if your lot size, topography, utility access, or project scope differs from the template, the fast-track does not apply, and you go through standard review (8–12 weeks). Check the city's website for available templates; if you find a match, ask the Planning Department if you can use the template plan set.
What happens if PG&E says they can't serve my ADU with a new meter — does my project die?
Not automatically, but it complicates things. If PG&E has no available capacity on your local feeder or requires a transformer upgrade (rare but possible), they will flag it in their feasibility letter. Solutions include: (1) requesting PG&E to defer service until capacity is available (timeline unknown); (2) exploring shared service with the primary home (single meter with internal load separation, unusual but possible); (3) exploring solar + battery to reduce grid demand; or (4) abandoning the project. Contact PG&E's development department early (before you commit to design and permits) to avoid this scenario. The city's Planning Department can facilitate an early PG&E conversation.
If I'm an owner-builder, do I still have to pay full permit fees?
Yes. Permit fees in Los Gatos are based on estimated construction value (1.5–2%), not on whether you're a licensed contractor or owner-builder. An owner-builder saving contractor markup does not translate to reduced permit fees. A $350,000 ADU project will cost $5,000–$7,000 in permit fees regardless. However, owner-builders can save on contractor overhead and markup, which is the real savings (typically 15–25% of hard costs). Licensed trades (electrical, plumbing) are still required and must be hired separately.