ADU rules in El Monte

El Monte permits a detached ADU on any residentially zoned or M/MU zoned lot with a proposed or existing dwelling (EMMC 17.110.030.C.1), and the citywide use matrix lists ADUs and JADUs as permitted in the R-1A, R-1B, R-1C, R-2, R-3, R-4, MMU and UMU zones (Table 17.A-1). The local track in Table 17.110-1 allows one detached ADU (or one attached ADU) plus one JADU on a single-family lot and up to two detached ADUs beside a multifamily building, while the state-exempt path in 17.110.030.U adds an 800 sq ft detached unit with 4 ft side and rear setbacks and up to eight detached units (never more than the existing unit count) on a lot with an existing multifamily building. There is no minimum lot size (C.2) and approval is ministerial. Two local limits yield to state law: U.1.c bars a new detached unit where the lot already has an attached ADU, which HCD's 6-24-2026 findings (item 18) say conflicts with the 'any combination' rule of Gov. Code 66323(a), and C.3 bars any ADU on a property developed with an SB 9 urban dwelling (item 6).

An ADU may be attached to or located within the proposed or existing primary dwelling, including attached garages and storage areas (17.110.030.D.1); 'attached' means sharing a wall with habitable space on both sides, not a connection by breezeway or patio cover (D.2). A single-family lot gets one attached or one detached ADU under Table 17.110-1, plus one JADU of up to 500 sq ft inside the home, and multifamily buildings may convert non-living space (storage rooms, boiler rooms, attics, basements, garages) into ADUs numbering up to 25 percent of the existing units, at least one (U.2.a). Conversions within existing space are approved on the state-exempt path in U.1.a, with up to 150 sq ft of expansion for ingress and egress. The side-or-rear entrance, no-exterior-staircase and no-upper-balcony rules in M.1-M.2 apply to attached units, and HCD's 6-24-2026 findings (items 10 and 11) say they cannot be imposed on JADUs or state-exempt units and exceed Gov. Code 66315 for other attached ADUs.

A new detached ADU may not exceed 850 sq ft for a studio or one bedroom or 1,000 sq ft for more than one bedroom (17.110.030.E.3); a new attached ADU is held to the same caps and to 50 percent of the existing or proposed primary dwelling (E.2). Conversions of an existing accessory structure have no size limit (E.4), JADUs are capped at 500 sq ft (E.1), and the state-exempt new-construction detached unit is 800 sq ft (U.1.b). Detached ADUs are limited to 16 ft, or 18 ft within one-half mile walking distance of a high-quality transit corridor or major transit stop, with roof-pitch alignment, or beside a multistory multifamily building (F.1); attached ADUs to 25 ft and one and one-half stories in R-1C and 30 ft and two stories elsewhere (F.2). Under Gov. Code 66321(b)(3) no percentage cap, lot coverage or FAR limit (J counts ADUs toward both) may block an ADU of at least 800 sq ft of interior livable space with 4 ft side and rear setbacks, and HCD's 6-24-2026 findings (item 7) say the R-1C one-and-one-half-story limit must allow two stories. If the city did not answer those findings within 30 days, Ord. 3053 is void under Gov. Code 66326(d) and the state default of 1,200 sq ft for a detached ADU (66314(d)(5)) applies instead (see caveats).

No owner-occupancy rule applies to ADUs: Ord. 3053 dropped the 2023 code's rule (former 17.110.030.S.2) that, from January 1, 2025, the owner live in the main home or the ADU on lots with ADUs permitted as of January 2, 2025, and Gov. Code 66315 bars such conditions. The codified text still requires every JADU lot to be owner-occupied (owner in the main home or the JADU, with a recorded covenant) unless the owner is a governmental agency, land trust or housing organization (17.110.030.R). Since January 1, 2026, Gov. Code 66333(b) limits that requirement to a JADU that shares sanitation facilities with the main home, which HCD's 6-24-2026 findings (item 16) direct the city to adopt; the Building Division's ADU and JADU Addressing Policy (effective April 23, 2026) already describes owner occupancy as applying to JADUs 'where sanitation is shared'.

Each ADU needs one parking space per bedroom or per unit, whichever is less, on top of the main home's parking; it may be uncovered and tandem on an existing driveway (17.110.030.H.2). No parking is required for a JADU (H.1), and none when the ADU is within one-half mile walking distance of public transit (any fixed-route bus stop or train station), inside the proposed or existing primary dwelling or an accessory building, where on-street permits are required but not offered, or within one block of a car-share vehicle (H.4). A garage, carport or uncovered parking structure removed to build an ADU need not be replaced (H.3), and units on the state-exempt path in 17.110.030.U are outside the H standards. The local list omits two state exemptions that apply anyway: ADUs in an architecturally and historically significant historic district (Gov. Code 66322(a)(2), HCD finding 8) and ADUs applied for together with a new single-family or multifamily dwelling (66322(a)(6)).

ADUs and JADUs are approved ministerially, without discretionary review or a hearing, through a Staff Level Zoning Clearance and building permit, with city action due within 60 days of a complete application (17.110.030.B.1, B.3); units on the state-exempt path go straight to a ministerially approved building permit (U). Chapter 17.120 lists new detached ADUs over 800 sq ft among projects needing a zoning clearance, decided by letter within 30 days and appealable to the Planning Commission (17.120.020.A.3.a, 17.120.040.C, 17.120.070). HCD's 6-24-2026 findings (items 3 to 5) say the ordinance must use the state approve-or-deny timelines (completeness in 15 business days, decision within 60 days of receipt) with an appeal process under Gov. Code 66317, and that a zoning clearance cannot block an 800 sq ft unit with 4 ft setbacks (66321(b)(3)). In the Rurban Homesteads Overlay any project resulting in more than one story needs director-level Design Review with mailed notice (17.22.040.E.5), a discretionary step state law does not allow for an ADU (66316, 66317).

ADUs and JADUs may be rented only for terms longer than 30 consecutive calendar days, and short-term rentals are prohibited (17.110.030.L.3). The zoning code defines a short-term rental as lodging for 30 or fewer consecutive nights (17.150.090) but lists it in no use table, so it is not permitted in any residential zone (17.20.040.B, 17.24.040.B), and pending Code Amendment No. 4-2026 would add it to every use table as a prohibited use. Detached ADUs may not be sold separately except under former Gov. Code 65852.26 (now 66341), and attached ADUs and JADUs may not be sold separately at all (L.1-L.2); HCD's 6-24-2026 findings (item 9) say the 66341 nonprofit exception must cover every ADU, and El Monte has adopted no Gov. Code 66342 condominium ordinance. The longer-than-30-day term matches Gov. Code 66323(e) and 66333(g) for state-exempt units and JADUs and is one day stricter than the 30-days-or-longer term 66315 allows for other ADUs. Landlords may also owe the Chapter 5.80 rental dwelling unit license tax ($50 per property plus $20 per unit a year), though its status for properties with three or fewer rental units is unclear: 5.80.060 records a 2000 suspension for them while 5.80.050 (Ord. 2966, 2020) sets calendar-year collection.