El Monte | ADUs and SB 9

El Monte, California ADUs and SB 9: Unit Sizes, the Zoning Clearance, State Law Overrides and Urban Dwellings

An accessory dwelling unit (ADU) is a second, smaller home on the same lot as a house or apartment building, with its own kitchen and bathroom. A junior ADU (JADU) is a unit of 500 square feet or less inside a house. SB 9 is the 2021 state law that allows two main homes on a single-family lot; El Monte calls each such home an urban dwelling. El Monte adopted its current text for both in May 2025. On several points that text is stricter than state law or disagrees with itself, and on those points the statute decides. This page sets out the City text, the overrides and the steps. The El Monte overview has the summary.

The ADU Rules (Section 17.110.030)

Section 17.110.030 opens by saying it is "established to comply with the state standards" and "shall be interpreted to be compatible with state enactments." It still cites "Sections 65852.2 and 65852.22 of the California Government Code." Those numbers were replaced in 2024; the state ADU rules now sit in Government Code 66314 and the sections after it. ADUs are allowed on "any residentially zoned or M/MU zoned lot that includes a proposed or existing dwelling," and "There shall be no minimum lot size."

• Size. "The maximum square footage for a junior ADU shall be five hundred (500) square feet." A new detached ADU "shall not exceed eight hundred fifty (850) square feet for a studio or one bedroom and one thousand (1,000) square feet for more than one bedroom." A new attached ADU has the same two caps and "shall not exceed fifty (50) percent of the existing or proposed primary dwelling." For a conversion of an existing accessory structure, "There shall be no size limit."
• Height. A detached ADU has "A maximum height of sixteen (16) feet in all zoning districts," with 18 feet in three listed cases. An attached ADU or JADU may reach "thirty (30) feet (two (2) stories)," or 25 feet and 1½ stories in R-1C.
• Setbacks. "The minimum interior side yard and rear yard setback for a detached ADU shall be four (4) feet," with none for a conversion or a rebuild "in the same location and to the same dimensions." A setback is the open distance a building must keep from a lot line.
• Parking. "No parking shall be required for a junior ADU." An ADU needs one space "for each ADU bedroom or ADU unit, whichever is less," which "may be provided as tandem parking on an existing driveway." Tandem means one car parked behind another. When a garage or carport is removed for an ADU, "replacement parking shall not be required."
• Driveways. A lot with one driveway may not add a second for a detached ADU "unless the proposed second driveway is accessed from an alley."
• Design. The entrance of an attached ADU or JADU "shall be located on the side or rear of the primary dwelling." The entrance of a detached ADU "shall not face, or be visible from the public right-of-way." "There shall be no upper story balconies or decks." A converted garage loses its garage door and gets "a three (3) foot wide planter" beside the driveway. Where these rules cannot be met, "the applicant may receive a waiver."
• Rentals and sale. A rental "shall be for a duration longer than 30 consecutive calendar days." An attached ADU or JADU "shall not be sold or otherwise conveyed separate from the primary residence."
• Sprinklers. ADUs "shall not be required to install fire sprinklers if they are not required for the existing single-family dwelling."
• Other lots. In the Rurban Homesteads overlay, ADU style and materials "shall match that of the primary building." On an existing flag lot, a garage or an ADU are the only new structures allowed on the pole.

Where the City Text Differs From State Law or From Itself

State law sets the minimum a city must allow. Government Code 66316 says that where a local ADU ordinance "fails to meet the requirements of this article, that ordinance shall be null and void" and the city applies the state standards. Subsection U of the El Monte section, headed "Exempt Units," repeats part of the state list and applies "Notwithstanding any development standard or other limitation set forth in subsections A. through S." It does not match the current statute on every point.

Sources: El Monte Municipal Code 17.110.030 (Supplement 36 Update 1); Gov. Code 66323, 66321, 66314, 66322, 66333 and 66311.5.

• Number on a house lot. Table 17.110-1 gives a lot with one house a detached ADU and a JADU, or an attached ADU and a JADU. Subsection U adds: "A new construction detached ADU shall not be permitted if the site includes an attached ADU." Government Code 66323(a) requires a city to approve "any combination" of a converted ADU, a JADU and "One detached, new construction, accessory dwelling unit" with a floor area limit "of not more than 800 square feet." A house lot may hold all three.
• Apartment lots. The table says "Maximum 2" detached ADUs on a lot with a multi-family structure. Subsection U allows "A maximum of eight (8) or equal to the number of existing units on the property," and two with a proposed building. Subsection U also places these units "Within an existing or proposed accessory building," and the statute has no such limit. Inside the building, both texts allow ADUs in unused space up to 25 percent of the existing homes, and at least one.
• Converted ADUs. Subsection U caps an ADU inside an existing house at "eight hundred (800) square feet or fifty (50) percent of the existing or proposed primary dwelling, whichever is less." The statute describes that unit as one "within the proposed space of a single-family dwelling or existing space" and sets no size.
• Height. Government Code 66321 requires 18 feet near transit, and "an additional two feet in height to accommodate a roof pitch on the accessory dwelling unit that is aligned with the roof pitch of the primary dwelling unit." The City lists roof pitch as a reason for 18 feet, with no added two feet.
• Setbacks for an attached ADU. Government Code 66314 allows "a setback of no more than four feet from the side and rear lot lines" for an ADU that is not a conversion. Under the statute a new attached ADU needs no more than four feet at the side and rear, where the R-1 zones ask for 5 feet at the side and 10 to 35 feet at the rear.
• Lot coverage and floor area. The City counts an ADU toward the zone's lot coverage and floor area ratio. The statute bars limits that do "not permit an accessory dwelling unit with at least 800 square feet of interior livable space and with four-foot side and rear yard setbacks."
• Parking. Government Code 66322 lists six cases with no parking, "whether or not the local agency has adopted an ordinance." The City text has four. The two missing cases are an ADU "within an architecturally and historically significant historic district" and one "submitted with a permit application to create a new single-family dwelling or a new multifamily dwelling on the same lot."
• Junior ADU owner rule. Subsection R requires that "Either the existing primary dwelling or junior ADU on a lot shall be occupied by the owner." Government Code 66333, as amended effective January 1, 2026, says "Owner-occupancy shall not be required if the junior accessory dwelling unit has separate sanitation facilities." The Building Division's April 2026 policy follows the statute: it speaks of "owner-occupancy for JADUs where sanitation is shared."
• Fees. Subsection S charges impact fees on "an ADU seven hundred fifty (750) square feet or larger." Government Code 66311.5 bars any impact fee on an ADU "that has 750 square feet of interior livable space or less." An ADU of exactly 750 square feet pays none. A larger one is charged "proportionately in relation to the square footage of the primary dwelling unit" in both texts.
• Commercial zones. The use matrix marks ADUs not permitted in C-1, C-2 and C-3, where it allows apartments by right. State law covers "areas zoned to allow single-family or multifamily dwelling residential use."

The Zoning Clearance, Step by Step

Section 17.110.030 makes ADUs and JADUs "subject to the requirements of this section and approval of a Staff Level Zoning Clearance." A zoning clearance is a staff check that plans meet the Zoning Code; Section 17.120.010 calls it a ministerial act, one where staff apply fixed written rules.

• What to file. The City's Zoning Clearance page asks for a site plan, floor plans and elevations, a "Planning Application signed by property owner (original wet signature document required)," a digital set of plans, one full-size set at 24 by 36 inches, and the fee.
• The fee. The fee schedule effective July 1, 2026 lists "Zoning Clearance (ADU or urban dwelling)" at $1,021.78. The City page says the fee covers the "first three (3) reviews." Each submittal after the third incomplete one costs $221.23.
• The time limit. The City "shall ministerially, and without discretionary review or a hearing, act on the application" within "sixty (60) days from the date the city receives a completed application." Section 17.120.040 asks for a decision letter "within thirty (30) days of deeming the application complete." Government Code 66317 adds a notice of completeness "not later than 15 business days" after filing, and says that after 60 days "the application shall be deemed approved."
• With a new house. Where the ADU is filed with a new house, the City "may delay acting" on the ADU until it acts on the house.
• How long it lasts. A zoning clearance is "valid for twelve (12) months," with one twelve-month extension.
• Building permit. The Building Division reviews the construction plans after the clearance. Its ADU and JADU Addressing Policy assigns an ADU address "during the building permit review and approval process." For a JADU, "No separate utility meters, service panels, or connections shall be approved or installed."

One code detail conflicts with the section itself. Section 17.120.020 lists a staff zoning clearance for "One or more new detached Accessory Dwelling Unit (ADUs), greater than eight hundred (800) square feet each," while Section 17.110.030 requires one for every ADU and JADU. The City page lists "Accessory Dwelling Units" with no size. The City's printed Applicant's Guide still cites "Chapter 17.18," the number used before the 2025 code; zoning clearances are now Chapter 17.120.

ADUs are a large share of new homes in El Monte. The staff report on the 2025 housing progress report, in the April 22, 2026 Council packet, counts 218 homes approved or permitted in 2025 and says "A total of 106 Accessory Dwelling Units (ADUs) obtained permits for construction."

SB 9 Urban Dwellings (Section 17.110.110)

Section 17.110.110 says the City "shall ministerially, and without discretionary review or a hearing, act on the application to create an urban dwelling." It names four cases: one urban dwelling beside an existing house, one beside a proposed house, two on "a property that is vacant or proposed to be vacant," and any of these filed with an urban lot split. A lot split is optional. The lot size and subdivisions page covers it.

Sources: El Monte Municipal Code Table 17.110-4 and Table 17.20-2 (Supplement 36 Update 1).

• Room for 800 square feet. Subsection M orders relief where a lot cannot fit two homes of 800 square feet each. Staff relax standards "in the following descending order": floor area ratio, lot coverage, building separation, enclosed parking, the front setback of a rear unit down to four feet, and parking. A third story is allowed only if "completely subterranean." No variance is needed.
• Sites excluded. Historic districts and landmarks, housing with rent limits, and "Housing that has been occupied by a tenant within the past three (3) years." A home "vacant and/or owner occupied for the past three (3) years may be fully demolished," and the applicant must prove it.
• Fees. "Such fees shall be charged at the same rate as a new single-family dwelling," and "New or separate utility connection shall be required."
• Recorded disclosures. Before occupancy the owner records that the homes "shall not be used for short term rentals" and that the urban dwelling "shall not be sold or otherwise conveyed separate from any other dwelling on the property."
• Order of occupancy. For new construction, the main house gets its certificate of occupancy, the City's sign-off that a building may be lived in, "at the same time or prior to the urban dwelling."

Where Section 17.110.110 and the Statute Differ

Government Code 65852.21, as amended effective June 30, 2026, says a city "shall not impose objective zoning standards, objective subdivision standards, and objective design standards that do not apply uniformly to development within the underlying zone," unless they are more permissive. The statute controls where the City text asks for more.

• Zones. The City allows urban dwellings "in One-Family Dwelling (R-1A or R-1B) zoning districts." The statute covers "a single-family residential zone." R-1C is a one-family zone in Table 17.14-1 and is left out of the City text. Ask the Planning Division how it treats an R-1C lot.
• ADUs on the same lot. A table note says "If the property is developed with 2 or more single-family, multiple-family dwellings, an Accessory Dwelling Unit (ADU) or Junior ADU, no urban dwelling(s) shall be permitted." Subsection K adds that after an urban dwelling is built, "no ADU or junior ADU shall be permitted thereafter." The statute says a city "shall not be required to permit an accessory dwelling unit or a junior accessory dwelling unit on parcels that use both the authority contained within this section and the authority contained in Section 66411.7," the lot split section. The City rule also reaches lots with no lot split.
• Setbacks for an attached unit. The table applies the zone setbacks to an attached urban dwelling. The statute says a city "may require a setback of up to four feet from the side and rear lot lines."
• Design guidelines. Subsection E says urban dwellings "shall comply with Chapter 17.140 (Design Guidelines)." That chapter adopts "comprehensive design guidelines of 2012." The statute allows only objective standards, ones that "involve no personal or subjective judgment by a public official."
• Extra reviews. Section 17.121.020 lists "developments with two (2) new urban dwelling units" for an initial plan review, and Table 17.122-1 lists two new units on a vacant lot for a minor design review. The statute requires a decision "within 60 days from the date the local agency receives a completed application," or the application "shall be deemed approved." Ask staff in writing which steps they require for an SB 9 project.
• Grounds to deny. The City text names none. The statute allows denial only on a written finding by the building official of "a specific, adverse impact" on "public health and safety."

Where to Go Next

Related on VanPlex: the El Monte overview, the California ADU law page and the SB 9 page.

Frequently Asked Questions

Official sources (checked October 2026)