Building an ADU in Santa Clarita

Which rules apply in Santa Clarita

Santa Clarita's ADU rules are in Section 17.57.040(L) of the Unified Development Code (Title 17 of the Municipal Code). The current text was adopted by Ordinance No. 26-2 on April 28, 2026. It says it implements state ADU law, "including, without limitation, Government Code Section 66323," and "Should any conflict arise between this subsection and California law, California law controls."

The rewrite followed a December 10, 2025 letter from HCD finding that the city's 2025 ADU ordinance (No. 25-1) and its SB 9 ordinance didn't comply with state law. HCD objected to, among other things, an owner-occupancy rule for new ADUs, corner-lot setbacks, a ban on mixing attached and detached ADUs, "compatible" architecture language, and replacement parking for garage JADUs. The 2026 text of 17.57.040(L) no longer contains those rules.

The city's ADU FAQ (March 2026) summarizes what you can build. For multifamily lots, or an ADU outside the categories below, the FAQ says to contact the Planning Division at (661) 255-4330. [1][2][4]

What you can build

The city's FAQ says "Under Government Code Section 66323, ADUs and JADUs on single-family properties are permitted," and answers "Yes, you may have each type of ADU on your property." That matches HCD's handbook: on a single-family lot, a city "must allow at least one ADU constructed from existing space, one JADU, and one newly constructed detached ADU."

The FAQ lists three types:

• Conversion of part of the house or an existing accessory structure: no maximum size, with setbacks sufficient for fire and safety. Converting an existing accessory structure can add up to 150 sq ft for entry and exit.
• New detached ADU: up to 800 sq ft, 4-foot side and rear setbacks, 16 feet tall. Within a half-mile of a transit stop, it can be 18 feet to the top plate plus 2 feet for a roof pitch of at least 2:12.
• Junior ADU: up to 500 sq ft, entirely within the walls of the house (including an attached garage) or an existing accessory structure.

Every ADU and JADU needs its own exterior access. The FAQ doesn't list standards for a detached ADU over 800 sq ft or an attached addition; state law sets limits a city can't go below (for example, at least 850 sq ft, or 1,000 sq ft with more than one bedroom, and heights of 16 to 25 feet depending on type and location). Ask Planning which standards apply before designing one of those. [2][5]

Parking

The city's FAQ says: "There are no parking requirements for ADUs or JADUs." The 2026 code text contains no ADU parking rule.

State law separately says parking for an ADU can never exceed one space per unit or bedroom, a garage converted or torn down for an ADU doesn't have to be replaced, and no parking can be required for the state's by-right ADUs or for a JADU. [1][2][5]

Fees and utility connections

Planning. The Planning Division fee schedule effective August 24, 2026 lists $425 for an "Accessory Dwelling Unit (ADU)." The city's applications page says over-the-counter approvals, which "usually involve residential additions, accessory dwelling units," are "processed at our Permit Center at no cost." Ask the Permit Center which applies to your project.

Impact fees. The code says ADUs and JADUs pay development impact fees "Except as provided in applicable law," charged "proportionally related to the square footage of the primary dwelling unit." State law exempts ADUs of 750 sq ft of interior livable space or less (and JADUs of 500 sq ft or less) from impact fees, and school districts can charge only ADUs over 500 sq ft.

Utility connections. The code says that, except as state law provides, each ADU and JADU must install a separate utility connection, with a connection fee or capacity charge proportionate to its burden on the water or sewer system. HCD's handbook says utilities can't treat an ADU or JADU as a new residential use for connection fees or capacity charges unless it is built along with a new single-family home. Confirm with your water and sewer provider. The city may also charge inspection and permit fees set by City Council resolution. For typical costs see our ADU cost guide. [1][3][5][6]

Junior ADUs

A JADU is up to 500 sq ft inside the walls of the house (including an attached garage) or an existing accessory structure. It needs an efficiency kitchen and may have its own bathroom or share the house's. A JADU can't be sold separately, can't be rented for less than 30 days, and must stay within the size and features the code allows.

The code requires the owner to live in the house or the JADU "unless exempt pursuant to applicable law, including without limitation Government Code Section 66333(b)," and the city's FAQ puts it this way: "Either the main home or JADU must be owner-occupied if sanitation facilities are shared." The city's posted JADU deed restriction form still requires owner occupancy in all cases and cites the old Gov. Code sections 65852.2 and 65852.22, which the state renumbered. If your JADU has its own bathroom, ask Planning which form to record.

A JADU without an internal connection to the house must apply for its own address number; one with an internal connection gets one only if the Building Official finds it necessary for safety. See our junior ADU guide and garage conversion guide. [1][2][7]

Renting, selling and occupancy

An ADU may be rented separately from the main house but can't be sold or otherwise conveyed separately, and any rental must be for 30 days or longer. You don't have to live on the property to have or rent an ADU.

The Building Official won't issue a final certificate of occupancy for an ADU or JADU before the main house has one, except as state law allows. ADUs and JADUs without an internal connection to the house need their own address number, posted over the entrance or where it can be seen from the street. [1][2][5]

Two homes and lot splits (SB 9)

Ordinance No. 26-2 also rewrote Section 17.57.025, the city's SB 9 rules. The Director must consider up to two homes on a single-family lot ministerially, as long as they meet state law and the zone's objective standards, and an urban lot split must be approved ministerially if it meets state law and Title 16 parcel map standards.

For a lot split, you sign an affidavit, before any final certificate of occupancy, to live in one of the two units as your principal residence for at least three years from approval, "unless otherwise exempt pursuant to California law." For a two-unit project, you record a covenant that all units are rented for 30 days or longer. HCD's December 2025 letter said the deed restriction and covenant rules in the city's earlier SB 9 ordinance were inconsistent with SB 9; ask Planning what you need to record. See our SB 9 lot split guide. [1][4]

Permit steps in Santa Clarita

1. Check the rules for your lot

   Read the city's ADU FAQ and call the Planning Division at (661) 255-4330, especially for multifamily lots or ADUs outside the FAQ's categories. [2][8]

2. Optional: request a One Stop Review

   For an early look at requirements and fees from several city departments, you can request a One Stop preliminary review; its fee is credited toward later entitlement fees. [3]

3. Get Planning approval at the Permit Center

   Bring your plans to the Permit Center at 23920 Valencia Boulevard, Suite 140, for over-the-counter review using the Over-the-Counter application. Call ahead to confirm hours. [3][8]

4. Record the JADU deed restriction (JADUs only)

   Complete and notarize the JADU deed restriction and record it with the County Recorder before the building permit is issued. [7]

5. Get building permits, an address and inspections

   Apply for building permits, apply for an address number if the unit has no internal connection to the house, and pass inspections. The final certificate of occupancy for the ADU follows the main house's. [1]

Who to call

• City of Santa Clarita Planning Division (Permit Center)

  ADU and JADU review, over-the-counter approvals, JADU deed restriction

  (661) 255-4330

  23920 Valencia Boulevard, Suite 140, Santa Clarita, CA 91355

  [2][8]

Questions people ask