Cotati City Council
Agenda Staff Report
Item type: PUBLIC HEARINGS (ACTION)
To: City Council
Subject: ADU ORDINANCE UPDATE
Date: August 25, 2026
Written by: Autumn Buss, Associate Planner
Recommendation
It is recommended by the Community Development Department that the City Council hold a public hearing and introduce an ordinance amending Section 17.42.170 Accessory Dwelling Units/Junior Accessory Dwelling Units of the Cotati Municipal Code to conform with State law.
Background
The State legislature makes frequent updates to State law on accessory dwelling units (ADUs), and in turn, the City is required to amend its code and/or adjust its review and permitting processes to conform with the new law. Most recently, AB 1154, SB 9, and SB 543 were approved in 2025 and went into effect January 1, 2026, necessitating action by the City. In addition, the State’s Housing and Community Development Department (HCD) recently reviewed the City’s ADU ordinance (CMC Section 17.42.170) and advised the City that several standards were not in conformity with State law and must be updated.
Analysis/Discussion
Overview of New State ADU Law
State legislation taking effect January 1, 2026 made the following changes:
AB 1154
1. JADU Owner-Occupancy: Whereas the existing state law required a property owner to reside in either the JADU or the remaining portion of the single-family structure (the primary dwelling), AB 1154 narrows this requirement to only apply when the JADU shares a bathroom with the primary dwelling. Now, if the JADU has its own bathroom, no owner occupancy is required on the property. This needs to be updated in the City’s code. (A JADU is a “junior” ADU that is up to 500 square feet in size, has its own kitchen, and is contained within the structure of a single-family dwelling.) Owner occupancy of properties with other types of ADUs is not required.
2. Minimum rental term: AB 1154 prohibits JADUs from being used as short-term rentals, setting a minimum rental term of 30 days. This requirement already exists in the City’s code (and applies to ADUs as well) and thus no update is needed.
SB 9
Previously existing ADU law requires local agencies to submit a copy of their ADU ordinance to the California Department of Housing and Community Development (HCD) within 60 days of adoption. SB 9 establishes a penalty for failing to do so by rendering null and void any local ADU ordinance that is not submitted to HCD on time. This does not affect the City’s code but necessitates compliance by City staff.
SB 543
1. Clarification of unit sizes: SB 543 amends references to allowable square footage of ADUs and JADUs to refer to “interior livable spaces.” This change needs to be made in the City’s code.
2. Impact fees: Existing law exempts ADUs of 750 square feet or less from development impact fees. The clarification that such fees should be based on “interior living space,” as well as that the exemption applies to JADUs, is set forth in SB 543. In addition, SB 543 exempts ADUs and JADUs with 500 or fewer square feet of interior living space from school impact fees. This change will apply to City internal processes and does not require a code update.
3. ADU permitting process: Local agencies have long been required by state law to approve or deny an ADU application within 60 days of receiving a completed application. However, state law has been silent with respect to the timing and process of incompleteness determinations, resubmittals, and appeals. SB 543 requires that local agencies make a determination of completeness within 15 days of application submittal and provide a list of incompleteness items, if applicable; review a resubmitted application within 15 days; provide applicant with a written appeal process for any incompleteness determination or denial; and provide a final written determination on the appeal within 60 days.
Since this is a process-related change, it does not need to be included in the City’s code. It should be noted that the City’s time to review ADU permit submittals and respond with completeness issues to applicants has been very expeditious and thus the 15 day time period does not present any concerns at this time. However, this requirement does have the potential to impact staff’s prioritization of projects and balance of workloads at some point in the future if conditions change, such as an economic uptick, for instance.
Summary of Amendments Requested by HCD
HCD staff recently reviewed the City’s ADU ordinance, identified a number of items that do not conform to the HCD staff’s interpretation of State ADU law, and requested that the City update its ordinance accordingly. The changes requested include the following:
1. Clarify that the City shall not deny an ADU permit application due to nonconforming zoning conditions, building code violations, or unpermitted structures that do not present a threat to public health and safety and are not affected by the construction of the ADU.
2. Remove language that states that ADUs/JADUs shall conform to development standards of the subject zoning district except as modified by the Section 17.42.170 or State law. HCD staff’s interpretation of State law is that no local standard may be required of ADUs/JADUs except the handful that are specifically allowed to jurisdictions in the law.
3. Add an exception that allows a detached ADU on a property where the primary dwelling was destroyed by a State-declared emergency to receive a certificate of occupancy before the reconstructed primary dwelling.
4. Remove the requirement that ADUs may only be located between the primary dwelling and the front property line when no other developable area is available on the property. The draft ordinance does include a limitation on size on front-yard ADUs to 800 square feet, which staff feels is consistent with State law. State law does not allow local jurisdictions to require front setbacks for such an ADU, however.
5. Clarify that square footage limits on ADUs are only applicable to ADUs on single-family lots or detached ADUs on multifamily lots. HCD maintains that State law does not allow size limits on attached ADUs on multifamily lots.
6. State that all ADUs are allowed an additional two feet of height to accommodate roof pitch.
Since the City’s ordinance does not reiterate all standards of the State law, but rather refers to State law as the controlling law, this height allowance has not been previously stated in the City’s code but was applied in practice.
The above-described changes are included in the draft ordinance amending Section 17.42.170.
A redline version of the proposed changes is included as Attachment A to this staff report.
Planning Commission Recommendation
On August 3, 2026, the Planning Commission held a public hearing and approved a resolution recommending that the City Council adopt the proposed ordinance.
Financial Considerations
Aside from the staff time required to prepare the draft ordinance, there are no financial impacts to the City from the adoption of this ordinance.
Environmental Issues
The proposed ordinance to amend Title 17 (Land Use) of the Cotati Municipal Code by amending Section 17.42.170 Accessory Dwelling Units/Junior Accessory Dwelling Units is exempt from the California Environmental Quality Act as the proposed ordinance is consistent with the program Final Environmental Impact Report (SCH# 2013082037) for the Cotati General Plan Update that was certified on March 24, 2015 (Resolution Number 2015-11) and the Mitigated Negative Declaration certified for the 2023-2031 Housing Element (SCH # 2013082037) adopted and certified on June 2, 2023; that this ordinance is consistent with and implements the City’s adopted General Plan, including the 2023-2031 Housing Element, and no new environmental impacts peculiar to the project site(s) have been realized or identified, therefore no additional environmental analysis is required under CEQA Section 15183, and therefore pursuant to Section 15168 of the CEQA Guidelines, as such no further environmental review is required.