ADU rules in Fresno County

In the unincorporated county a detached ADU needs only a ministerial building permit wherever Article 2 lists ADUs as permitted: the AE, AL, A-1 and A-2 agricultural zones, the R-A, R-R, R-1 family, R-2 and R-3 residential zones, and the C-P, C-4 and R-P commercial zones (the C-6 zone needs a conditional use permit). Section 834.4.030.B.3 prohibits ADUs and JADUs in the mapped Low Water Area, generally east of the Friant-Kern Canal or west of Interstate 5, which the county's GIS layer draws over about 3,780 of the county's roughly 6,010 square miles (including national forest and park land) and which takes in the foothill and mountain communities such as Auberry, Prather, Tollhouse, Shaver Lake, Big Creek, Squaw Valley and Dunlap, and it also bars them on any parcel under two acres served by a private well and septic system; the county's ADU page and its June 2026 handout F417 still say ADUs are 'currently not allowed within low water areas'. Where ADUs are allowed, a single-family lot may have one detached unit, either the state-model 'Limited Detached' unit (800 sq ft or less, 16 feet, 4-foot side and rear setbacks) or a larger unit under the 834.4.030.B.7 size limits, together with one JADU or one attached ADU. State law reaches further than the county text: Gov. Code 66323(a) requires ministerial approval of the state-exempt units (a conversion ADU, a JADU and an 800 sq ft detached unit) in any residential or mixed-use zone 'notwithstanding Sections 66314 to 66322', and HCD's March 2026 handbook says water-and-sewer area designations under 66314(a) 'cannot preclude units described in Government Code section 66323', so under state law the ban can lawfully reach only the larger county-standard units; no HCD letter or county statement has tested this. Inside the Low Water Area the county's own alternative is a discretionary second dwelling unit (Director Review and Approval with an owner-occupancy covenant), not an ADU.

Attached ADUs (new space sharing a wall, floor or ceiling with the home) and converted ADUs (space inside the home, an attached garage or an existing accessory structure, plus up to 150 sq ft for entry) need only a building permit in the same zones, and fall under the same Low Water Area and under-two-acre well-and-septic prohibitions, as detached units (834.4.030.B.3-4). On a single-family lot the county allows only one attached or converted ADU or one JADU, plus one detached ADU (834.4.030.B.5.b-c), whereas Gov. Code 66323(a)(1)-(2) requires allowing a conversion ADU and a JADU and a new detached unit together, which HCD's handbook describes as 'at least one ADU constructed from existing space, one JADU, and one newly constructed detached ADU'. In an existing multifamily building, ADUs may be carved from non-livable space such as storage rooms, garages, attics or basements, at least one and up to 25 percent of the existing units (834.4.030.B.5.d(1), matching 66323(a)(3)). JADUs of up to 500 sq ft inside a single-family home, with an efficiency kitchen, are allowed with a ministerial building permit and a recorded deed restriction (834.4.030.B.4.c, B.9). The same state-law override described for detached units applies: in residential and mixed-use zones the conversion ADU and the JADU are 66323 units that area designations cannot preclude.

For new attached and detached ADUs, 834.4.030.B.7.a, as amended by Ord. T-104-390 (effective March 12, 2026), sets 850 sq ft for a unit with fewer than two bedrooms and 1,000 sq ft for two bedrooms, allows no more than two bedrooms, and adds that a unit may not exceed 50 percent of the primary dwelling's floor area with 'a maximum of 1,200 square feet'; read literally the bedroom caps leave the 1,200 sq ft ceiling unreachable, the adopting staff report describes the change only as 'size clarifications', and the county's free pre-approved plans stop at 1,000 sq ft, so this entry treats 850 and 1,000 sq ft as the caps (low confidence: confirm how Development Services applies the 1,200 figure). State law overrides the percentage cap where it would bite: Gov. Code 66321(b)(3) forbids any percentage-of-home limit that does not permit an ADU of at least 800 sq ft of interior livable space with 4-foot side and rear setbacks, and since January 1, 2026 the 850 and 1,000 sq ft floors of 66321(b)(2) are measured as interior livable space, while the county text does not say how it measures floor area. The 'Limited Detached' state-exempt unit is capped at 800 sq ft (834.4.030.B.5.b(2); Gov. Code 66323(a)(2)), conversions of existing space have no cap beyond a 150 sq ft entry expansion, and JADUs are capped at 500 sq ft with no more than 150 sq ft added to the house (834.4.030.B.9(1)). Single-story attached and detached ADUs are limited to 16 feet to the peak; a two-story detached ADU is allowed only in the AE, AL, A-2, R-R, R-C and R-S zones, up to the zone height, and two-story attached units follow state law, which allows attached ADUs 25 feet or the zone's limit, whichever is lower (66321(b)(4)(D)). Anything larger (900 to 2,000 sq ft) is possible only as a discretionary second dwelling unit under 834.4.030.C.

No for ADUs: Section 834.4.030.B imposes no owner-occupancy condition on attached, detached or converted ADUs, consistent with Gov. Code 66315, which bars owner-occupant requirements for ADUs. For JADUs the county text still requires, with no exception for a JADU with its own bathroom, that a person with legal or equitable title live in the house or the JADU (834.4.030.B.4.c(2)), and a recorded deed restriction; since January 1, 2026 Gov. Code 66333(b), as amended by AB 1154, allows that requirement only when the JADU shares sanitation facilities with the main home, and 66339.5 makes the state JADU article supersede conflicting local text, so a JADU with separate sanitation carries no owner-occupancy duty. The county's larger discretionary 'second dwelling units' (834.4.030.C) are a separate product and do require a recorded covenant that an owner of record occupy one of the two units, with the approval terminating if neither is owner-occupied. The adopted 2025 Housing Element's statement that JADU owner occupancy applies only when an ADU and a JADU share a parcel matches neither the code nor state law.

Section 834.4.030.B.7.e(1) requires one off-street space for each new attached or detached ADU, in addition to the home's own parking; it may be tandem on an existing driveway or on a mechanical lift, but no parking is allowed in the front yard except on the paved driveway. No space is required within one-half mile walking distance of public transit, in a historic district, for a unit that is part of the home or an accessory structure, where on-street permits are required but not offered to the occupant, or within one block of a car-share space (B.7.e(3), tracking Gov. Code 66322(a)), none for converted ADUs or JADUs (B.8(2), B.9(3)), and a garage, carport or covered parking structure demolished or converted for an ADU never has to be replaced (B.7.e(2); 66314(d)(11)). The county text does not exempt the 800 sq ft 'Limited Detached' state-exempt unit, but Gov. Code 66323(b) bars any development standard that section does not authorize, and HCD's handbook lists parking among the standards that cannot be imposed on 66323 units. The state ceiling is one space per unit or per bedroom, whichever is less (66314(d)(10)), so the county's one space per unit is the most that can be required. Discretionary second dwelling units need two spaces, one covered (Table 3-7; 834.4.030.C.1.d).

Attached and detached ADUs need only a building permit, which 834.4.030.B.7.f(1) calls a 'Ministerial Accessory Dwelling Unit Permit' that the county must issue within 60 days of a complete application (tolled for applicant delays or corrections, or deferred until a concurrent new-home permit is acted on); converted ADUs and JADUs likewise get a ministerial building permit (B.8(3), B.9(4)), consistent with Gov. Code 66317 and 66335. Applications are filed through the county's Citizens Portal with a zoning review inside plan check, and the Building and Safety division offers nine free pre-approved plan sets (500, 749 and 1,000 sq ft; permit fees about $2,370 to $3,070). Exceptions: ADUs in the C-6 zone need a conditional use permit (Table 2-6), and a unit that exceeds the ADU size limits, or sits where the ADU location limits bar it, can only be built as a 'second dwelling unit' through Director Review and Approval, a discretionary permit (834.4.030.C; Tables 2-2, 2-4, 2-4-1).

An ADU may be rented but not sold or conveyed separately from the parcel and the primary dwelling (or, on a multifamily parcel, from all the dwellings) unless state law permits it (834.4.030.B.6.g), and no ADU may be rented for a term shorter than 30 days (B.6.h), a rule that also covers JADUs. A 30-day lease satisfies the county text and Gov. Code 66315 for a county-standard ADU, but state-exempt units under 66323 (the 800 sq ft 'Limited Detached' unit and conversions) and JADUs must be rented for terms longer than 30 days (66323(e), 66333(g)). The unincorporated county has no short-term rental ordinance or permit program: the Ordinance Code has no STR chapter and the Zoning Ordinance mentions 'Short-Term Private Home Rental' only as a parking line in Table 3-7, so the 30-day floor is what bars short-term use of an ADU. The county levies no transient occupancy tax today; Ordinance No. 26-004 (adopted April 21, 2026) would impose a 12 percent tax on stays of 30 days or less in the unincorporated area only if voters approve it on November 3, 2026 (Resolution No. 26-257, requested as Measure A). Separate sale is limited to the qualified-nonprofit path of Gov. Code 66341; no Gov. Code 66342 ADU-condominium ordinance appears in the Zoning Ordinance or the Board record.