From: James Lloyd
To: City Council (San Mateo); Adam Loraine; Nicole Fernandez; Danielle Cwirko-Godycki; Lisa Diaz Nash; Rob Newsom
Cc: City Attorney"s Office; Clerk; City Mgr; Community Development Distribution Subject: public comment re item 17 for tonight"s Council meeting Date: Monday, January 26, 2026 2:08:59 PM
Attachments: San Mateo - ADU Ordinance - 26 Jan 2026 - CC.pdf Dear San Mateo City Council,
The California Housing Defense Fund (“CalHDF”) submits the attached public comment concerning Item 17 on the agenda for the January 26, 2026 Council meeting, an update to the City’s regulations for the development of accessory dwelling units (“ADUs”) and junior accessory dwelling units (“JADUs”).
James M. Lloyd
Director of Planning and Investigations
California Housing Defense Fund
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Jan 26, 2026
City of San Mateo
330 West 20th Avenue
San Mateo, CA 94403
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Re: Proposed Amendments to the City’s ADU Regulations
Dear San Mateo City Council,
The California Housing Defense Fund (“CalHDF”) submits this letter as a public comment concerning Item 17 on the agenda for the January 26, 2026 Council meeting, an update to the City’s regulations for the development of accessory dwelling units (“ADUs”) and junior accessory dwelling units (“JADUs”).
CalHDF applauds the City for updating its ADU regulations to keep pace with changes in state law. CalHDF writes to
flag specific legal issues with the ordinance, which the City should address before passing the ordinance.
Of note, the staff report indicates that our comments have been disregarded merely because HCD did not highlight these issues in their review of the ordinance. HCD reviewers are human, and they do not always catch every issue. CalHDF is currently litigating against multiple cities that have noncompliant ADU ordinances, and HCD has not always caught the areas of noncompliance in their reviews of those cities’ ADU ordinances. The City should independently evaluate our comments based on their content and state ADU law.
Background
The law gives local governments authority to enact zoning ordinances that implement a variety of development standards on ADUs. (Gov. Code, § 66314.) The standards in these local ordinances are limited by state law so as not to overly restrict ADU development. (See id.) Separately from local ADU ordinances, Government Code section 66323 establishes a
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narrower set of ADU types that local governments have a ministerial duty to approve. “Notwithstanding Sections 66314 to 66322 ... a local agency shall ministerially approve” these types of ADUs. (Id. at subd. (a).) This means that ADUs that satisfy the minimal requirements of section 66323 must be approved regardless of any contrary provisions of the local ADU ordinance. (Ibid.) Local governments may not impose their own standards on such ADUs. (Gov. Code, § 66323, subd. (b) [“A local agency shall not impose any objective development or design standard that is not authorized by this section upon any accessory dwelling unit that meets the requirements of any of paragraphs (1) to (4), inclusive, of subdivision (a).”].) In addition, ADUs that qualify for the protections of Government Code section 66323, like other ADUs, must be processed by local governments within 60 days of a complete permit application submittal. (Gov. Code, § 66317, subd. (a).)
State law also prohibits creating regulations on ADU development not explicitly allowed by state law. Government Code Section 66315 states, “No additional standards, other than those provided in Section 66314, shall be used or imposed, including an owner-occupant requirement, except that a local agency may require that the property may be used for rentals of terms 30 days or longer.”
Impermissible Size Limits on Exemption ADUs on Multifamily Parcels
Code section 27.19.070(c) generally restricts detached ADUs on multifamily parcels to 800 square feet in size. The code does this by only allowing floor area ratio waivers for ADUs up to 800 square feet in size and also only allowing ADUs to be as large as the smallest existing unit on the property, unless the smallest unit is less than 800 square feet, in which case the ADU may be 800 square feet in size.
However, the City should be aware that such size restrictions are not permitted for new construction, detached ADUs on multifamily parcels. Government Code section 66323 subdivision (a)(4) allows up to eight detached ADUs on multifamily parcels without size restrictions. Size restrictions are plainly forbidden by Government Code, section 66323, subdivision (b), which explicitly exempts statewide exemption ADUs from all local standards:
“(b) A local agency shall not impose any objective development or design standard that is not authorized by this section upon any accessory dwelling unit that meets the requirements of any of paragraphs (1) to (4), inclusive, of subdivision (a).” Because Government Code section 66323 subdivision (a)(4) does not contain a size limit for new construction, detached ADUs on multifamily parcels, the City may not unilaterally impose one.
HCD reaffirms this requirement of state law on page 20 of the January 2025 HCD ADU Handbook (emphasis added):
A local agency may not impose development or design standards, including both local standards and standards found in State ADU Law, on 66323 Units that are not specifically listed in Government Code section 66323. (Gov. Code, § 66323, subds. (a),
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(b).) This includes, but is not limited to, parking, height, setbacks, or other zoning provisions (e.g., lot size, open space, floor area ratio, etc.).
The City must exempt ADUs developed pursuant to Government Code section 66323, subdivision (a)(4) from all size restrictions.
Parking
Staff is recommending exempting all ADUs from offstreet parking requirements citywide.
CalHDF strongly supports this recommendation. This will encourage ADU development and will help the City meet its RHNA targets.
However, regardless of what the City decides to do in terms of parking requirements, the City should be aware that it cannot require parking for ADUs that conform to the requirements of Government Code section 66323, subdivision (a), as section 66323, subdivision (b) specifically exempts such ADUs from all local requirements.
From page 20 of the January 2025 HCD ADU Handbook (emphasis added):
A local agency may not impose development or design standards, including both local standards and standards found in State ADU Law, on 66323 Units that are not specifically listed in Government Code section 66323. (Gov. Code, § 66323, subds. (a), (b).) This includes, but is not limited to, parking, height, setbacks, or other zoning provisions (e.g., lot size, open space,
floor area ratio, etc.).
In its update to its ADU regulations, the City must exempt section 66323 ADUs from all parking requirements, as is required by state law.
Impermissible Discretionary Process
City Code section 27.19.045 contains a discretionary approval process for ADUs that do not meet code requirements. Such a process is forbidden by state law.
Government Code section 66317, subdivision (a) forbids all discretionary review for ADU approvals: “A permit application for an accessory dwelling unit or a junior accessory dwelling unit shall be considered and approved ministerially without discretionary review or a hearing, notwithstanding Section 65901 or 65906 or any local ordinance regulating the issuance of variances or special use permits.”
The City must therefore eliminate any discretionary review of ADUs.
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James M. Lloyd
CalHDF Director of Planning and Investigations
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