Town Permit Guide

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Can I build an ADU in Los Gatos, California?

Los Gatos, Santa Clara County · Ordinances checked 2026-10-05 · Reviewed · 15 cited sections

Allowed with a permit

Yes. On a single-family lot Los Gatos allows one ADU plus one junior ADU (up to 500 sq ft inside the house), approved ministerially through a Building Permit within 60 days. ADUs can be up to 1,200 sq ft, one story, and 16 feet tall if detached, with 4-foot side and rear setbacks; the owner must live on site only when there is a junior ADU.

Units on a single-family lot1 ADU + 1 junior ADU [1]
ApprovalMinisterial Building Permit; Town acts within 60 days [2]
Max ADU size1,200 sq ft [3]
Attached ADU size50% of the main home, but 800 sq ft always allowed [4]
Max height, detached ADU16 feet (one story) [5]
Side (incl. street-side) and rear setbacks (new detached ADU)4 feet minimum [7]
Parking1 space per ADU or per bedroom, whichever is less (many exemptions) [8]
Junior ADU max size500 sq ft [10]
Owner-occupancyRequired only with a junior ADU [11]
Short-term rentalRentals under 30 days prohibited [12]

What you can build

ADUs and junior ADUs (JADUs) are allowed on any parcel zoned for single-family or multi-family homes that has an existing or proposed main house. On a single-family lot the code allows one JADU inside the house and one ADU [1]. Applications that meet the standards are reviewed ministerially as a Building Permit, with no public hearing or appeal, and the Town must act within 60 days of a complete application [2].

Size, height and placement

An ADU can be up to 1,200 square feet [3]. An attached ADU that isn't a conversion is capped at 50 percent of the main home, but 800 square feet is always allowed [4]. A detached ADU is limited to 16 feet [5] (18 feet near major transit) and every ADU must be one story [6]. In the setback table (Table 1-2), a new detached ADU on a single-family lot needs at least 4 feet from the rear [7] and side lot lines, including a street-side line [15], 5 feet from other buildings, and the zone's front setback (which can't block an 800-square-foot ADU); they can't sit in front of the house except in HR zones [13]. ADUs are exempt from lot coverage limits and get 800 square feet of floor-area exemption. Objective design standards apply: matching exterior materials, no balconies or second-story decks, and clerestory windows near property lines.

Junior ADUs

A JADU must be within the walls of the house (an attached garage counts) and can't exceed 500 square feet [10]. It needs a separate entrance and at least an efficiency kitchen.

Parking and fees

One space per ADU or per bedroom, whichever is less, is required [8], but not within a half mile walk of public transit [9], for conversions, for JADUs, or when a garage is converted. ADUs under 750 square feet and JADUs pay no impact fees [14].

Occupancy and rentals

No owner-occupancy rule applies to an ADU, but the owner must live in the house when there is a JADU, recorded by deed restriction [11]. State law now allows that requirement only for a JADU that shares a bathroom with the house, so state law may override this broader rule. Rentals under 30 days are prohibited [12].

Pending changes

This division dates from 2023, and the Town is updating its ADU ordinance; check for a newer version before you apply. State law may also allow more units than the one-ADU limit shown here (for example a converted ADU plus a JADU plus a new detached ADU), and starting January 1, 2027, state law (AB 956) will require cities to allow two new detached ADUs on a single-family lot.

See how Los Gatos compares with 8+ other California towns on accessory dwelling units (adus) →

Next steps

  1. Read Town Code Chapter 29, Division 7 and the Town's ADU summary handout, and check whether the pending ADU ordinance update has been adopted.
  2. Confirm your zoning, setbacks and transit distance with the Planning Division (408-354-6874).
  3. Submit the combined ADU/JADU Building Permit application (or use a pre-approved plan from the Town's ADU Plans Gallery); questions on building code go to the Building Division (408-354-6876).
  4. For a JADU, record the Town's deed restriction before the Building Permit is issued.

Common questions

Are ADUs allowed in Los Gatos, California?
Yes. On a single-family lot Los Gatos allows one ADU plus one junior ADU (up to 500 sq ft inside the house), approved ministerially through a Building Permit within 60 days.
How big can an ADU be in Los Gatos, California?
ADUs can be up to 1,200 sq ft, one story, and 16 feet tall if detached, with 4-foot side and rear setbacks. An attached ADU can be 50% of the main home, but 800 sq ft is always allowed.
Do I need to live on the property to have an ADU in Los Gatos, California?
The owner must live on site only when there is a junior ADU.
Can I rent my ADU short term in Los Gatos, California?
No. Rentals under 30 days are prohibited for ADUs.

California's statewide ADU law

California's ADU law (Gov. Code §§66310–66342, recodified from §65852.2; latest amendments effective January 1, 2026) overrides conflicting city rules, including in charter cities. Cities must approve ADUs ministerially (no hearing) within 60 days of a complete application, or the permit is deemed approved.

What cities cannot require or do:

  • Owner-occupancy for an ADU.
  • A minimum lot size.
  • Side or rear setbacks over 4 feet for a new ADU, or any setback for a converted existing structure.
  • Size, lot coverage or floor-area rules that block an ADU of at least 800 sq ft. Size caps can't be under 850 sq ft (1,000 for 2+ bedrooms).
  • Parking within half a mile walking distance of public transit, or replacement parking for a garage converted to an ADU.
  • Impact fees on ADUs of 750 sq ft or less.

By right on a single-family lot: one converted ADU plus one junior ADU (JADU, up to 500 sq ft inside the house), plus one new detached ADU (up to 800 sq ft, 16 ft tall). Owner-occupancy may be required only for a JADU that shares a bathroom.

Short-term rentals: cities may bar ADU rentals under 30 days, and must for by-right ADUs, JADUs and SB 9 units.

Coming January 1, 2027: AB 956 raises the by-right count to two new detached ADUs per single-family lot.

SB 9 (§§65852.21, 66411.7) allows two homes on a single-family lot, or a split into two lots of at least 1,200 sq ft (with a 3-year owner-occupancy affidavit).

State sources: Gov. Code §66314 (ADU ordinance standards) · Gov. Code §66315 (no owner-occupancy requirement) · Gov. Code §66317 (ministerial review, 60-day deadline) · Gov. Code §66321 (size, setback and height limits on local rules) · Gov. Code §66322 (parking exemptions) · Gov. Code §66323 (by-right ADUs and JADUs) · Gov. Code §66333 (junior ADUs) · Gov. Code §66311.5 (impact fees) · AB 956 (2026), Stats. 2026, ch. 791 · Gov. Code §65852.21 (SB 9 two-unit projects) · Gov. Code §66411.7 (SB 9 urban lot splits) · HCD, Accessory Dwelling Units (ADU Handbook, updated March 2026)

What the ordinance says

Exact text from Los Gatos's published ordinances. Section numbers are as printed in the source.

  1. Sec. 29.10.320(c)(1), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    Not more than one (1) junior accessory dwelling unit contained within the space of a proposed or existing single-family dwelling, and one (1) accessory dwelling unit, may be permitted on a lot with a proposed or existing primary dwelling.
  2. Sec. 29.10.315(a), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    Development of an accessory dwelling unit and/or junior accessory dwelling unit consistent with this division shall be reviewed ministerially as a Building Permit and the Town shall take final action within sixty (60) days of submittal of a complete application.
  3. Sec. 29.10.325(c)(1), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    The maximum floor area of an accessory dwelling unit is one thousand two hundred (1,200) square feet.
  4. Sec. 29.10.325(c)(2), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    An attached accessory dwelling unit that is not created though conversion of existing space shall not exceed fifty (50) percent of the size of the existing primary dwelling. Exception: Up to eight hundred (800) square feet of gross floor area of an attached accessory dwelling unit shall be exempt from this subsection.
  5. Sec. 29.10.325(f)(1), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    A height of sixteen (16) feet for a detached accessory dwelling unit on a lot with a proposed or existing single-family or multi-family dwelling.
  6. Sec. 29.10.325(e), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    Accessory dwelling units shall be contained within one (1) story.
  7. Sec. 29.10.325(b), Table 1-2 (Rear row; single-family new detached ADU column), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    Rear 4 feet minimum
  8. Sec. 29.10.320(f), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    One (1) parking space per accessory dwelling unit or per bedroom, whichever is less, shall be provided in addition to the required minimum number of parking spaces for the primary dwelling.
  9. Sec. 29.10.320(f)(1)b., Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    The accessory dwelling unit is located within one-half (½) mile walking distance of public transit.
  10. Sec. 29.10.330(c), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    The maximum floor area of a junior accessory dwelling unit is five hundred (500) square feet, measured from the outer face of exterior walls and the centerline of shared interior walls.
  11. Sec. 29.10.330(g), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    The property owner shall reside in the single-family residence in which the junior accessory dwelling unit will be located.
  12. Sec. 29.10.320(s), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    Rentals for durations of less than thirty (30) days, including short-term rentals (as defined by the California Government Code), are prohibited.
  13. Sec. 29.10.325(a)(1), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    No detached accessory dwelling unit may be constructed in front of the primary dwelling except in the HR zones.
  14. Sec. 29.10.365(b), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    An accessory dwelling unit less than seven hundred fifty (750) square feet or a junior accessory dwelling unit is exempt from impact fees imposed by the Town, special district, or water corporation.
  15. Sec. 29.10.325(b), Table 1-2 (Side row; single-family new detached ADU column), Town Code Chapter 29, Article I, Division 7 - Accessory Dwelling Units, p. 1
    Side (including street-side) 4 feet minimum
This page summarizes Los Gatos's posted ordinances as of 2026-10-05. Ordinances are amended, and individual lots can have overlays, subdivision covenants, or HOA rules that are stricter. Confirm with Community Development - Code Compliance (Building Division 408-354-6876), 110 E. Main St. (408-399-5720) before you build. Spot an error?