Costa Mesa updates ADU ordinance to align with state mandates and increase housing options

The Costa Mesa City Council convened on March 18, 2025, to discuss significant updates to the city’s Accessory Dwelling Unit (ADU) ordinance, prompted by recent state mandates. The meeting began with a presentation outlining the necessity for these updates due to changes in California government code that rendered the existing ordinance obsolete.

The proposed ordinance revisions aim to align with three specific state bills—SB 477, SB 1211, and AB 2533—which enhance flexibility for developers and facilitate the legalization of previously unpermitted ADUs. The updated ordinance allows for increased numbers of ADUs on single-family and multi-family properties, including provisions for one conversion ADU and one Junior ADU (JADU) within the main dwelling, plus an additional detached or attached ADU.

Key changes include:
- For single-family homes, the allowance of one conversion ADU, one JADU, and one additional detached or attached ADU.
- For multi-family properties, the potential for up to eight detached ADUs, provided they do not exceed the number of existing units.
- Adjustments to maximum square footage for ADUs to comply with state standards, allowing for up to 1,000 square feet for larger units.

The council also introduced a "safe ADU legalization program" to enable homeowners with unpermitted ADUs built before January 1, 2020, to legalize their structures. This initiative aims to bring these units into compliance with building codes.

During the meeting, council members raised questions regarding the ordinance's implications, including the potential for short-term rentals of JADUs, which the city staff opposed, citing concerns about reducing long-term rental availability. The council emphasized the importance of maintaining affordable housing options in the community.

Public comments reflected a mix of support and concern regarding the ordinance. Some residents expressed apprehension about the impact of increased density on neighborhood character, while others highlighted the necessity of expanding housing options in response to California's housing crisis.

After thorough discussion, the council unanimously approved the ordinance for first reading, with a motion to clarify certain language regarding recommendations versus requirements in the ordinance. The council's decision marks a proactive step towards enhancing housing availability in Costa Mesa while adhering to state regulations. The next steps will involve further refinement of the ordinance and continued engagement with the community to address concerns and feedback.