Owning a single-family lot in Mission Viejo can raise questions about whether a lot split or another dwelling is possible. According to the city’s meeting summary, the City Council adopted Ordinance 26-363 on October 13, 2026. It addresses SB 9 lot splits and two-unit projects, replacement housing, residential land uses and height limits in certain multifamily districts.
This is general information and not legal advice.
What did the city adopt, and when does it take effect?
The City Council adopted amendments to Title 9 of the Mission Viejo Municipal Code, and the ordinance says it takes effect 30 days after passage. The council introduced the ordinance on September 22, 2026 by a 4-0 vote with one abstention.
The October 13 meeting summary reports adoption under consent calendar Item 9. The summary is informational; approved minutes are the official record of the action. You can check the city’s agenda portal for meeting documents.
The amendments implement Programs 4 and 13 of the city’s certified 2021-2029 Housing Element. The California Department of Housing and Community Development certified that Housing Element on February 8, 2024. The Housing Element page provides the city’s housing planning context.
For a property inquiry, identify Ordinance 26-363 and its case numbers: P-ZC2026-0002 and P-DCA2026-0003.
What changes for an SB 9 lot split or two-unit project?
The ordinance places development under new Development Code Section 9.10.020(b)(14), “Residential Lot Splits,” under staff review and approval using that section’s criteria and standards.
The July 13 staff report, included in the September agenda packet, explains that SB 9 requires ministerial approval for qualifying two-unit developments, qualifying urban lot splits, or both, on parcels zoned for single-family residential use. Ministerial approval means approval without discretionary review or public hearings.
According to that report, SB 9 makes up to four total housing units possible on parcels that previously allowed a single home. The word “qualifying” matters. Ask the Planning Division which criteria your parcel and proposed project must satisfy.
The ordinance also says this chapter applies only while the Government Code sections created by SB 9 remain in effect. Altadena’s SB 1090 lot split pause shows why lot split questions need local context. For a Mission Viejo parcel, ask the city’s Planning Division about eligibility under its section.
What limits apply to units created under the SB 9 section?
Units created under this section cannot be short term rentals, and any rental must last at least one month.
The full ordinance in the October 13 agenda packet also addresses connected buildings. An application cannot be rejected solely because it proposes adjacent or connected structures, provided they meet applicable building code standards.
There is a stated basis for denial. The city may deny construction of dwelling units under this section if the Building Official makes a written finding, based upon a preponderance of the evidence, that the proposed units would have a specific adverse impact on public health and safety or the physical environment, with no feasible way to satisfactorily mitigate or avoid it.
Say a buyer considers a single-family property because an SB 9 project might be possible. The buyer would ask the Planning Division whether the parcel and proposed development qualify, then check the section’s standards before treating additional units as part of the purchase plan. If the buyer intends to rent a unit created under that section, the rental would need to last at least one month. If the property has an HOA, the buyer would also read its governing documents and ask the city and HOA how those documents relate to the proposal.
For readers comparing rental requirements across cities, Vista’s short term rental guide covers that topic in another city.
When does replacement housing become part of a project?
New Chapter 9.61, “Replacement Housing Requirements,” applies in every zoning district that allows multifamily residential uses.
Its stated purpose is to prevent housing loss and displacement of lower income households. The chapter directs the city to approve and issue a building permit for a housing development project requiring demolition when it creates at least as many dwelling units of equivalent size as will be demolished. “Equivalent size” means at least the same total number of bedrooms.
Projects proposing demolition or conversion of multifamily units must replace all existing or demolished protected units. The protected categories include units with specified affordability restrictions, public rent or price controls, or occupancy by lower or very low income households within the stated five-year period. Units withdrawn from rental under the Ellis Act within the past 10 years are also included.
The written replacement application goes to the Planning Division and is processed alongside the project’s other entitlements. The chapter’s definition of a housing development project excludes a project within a very high fire hazard severity zone. Ask the division how that exclusion and the replacement requirements apply to your proposal.
Which building height limits changed?
Height limits increased in the multifamily RPD 30, RPD 50 and RPD 80 districts.
The staff reports give these changes:
RPD 30 rises from 35 feet to 40 feet, and from two stories to three stories.
RPD 50 rises from 50 feet to 55 feet.
RPD 80 rises from 65 feet to 84 feet.
The single-family RPD 3.5 and RPD 6.5 columns show 35 feet and two stories, with no change described. These district standards don’t establish that any particular property or neighborhood will receive taller buildings. Ask the Planning Division which district applies to the parcel you’re considering.
Say a buyer considers a multifamily property in the RPD 30 district and wants to understand the ordinance’s height changes. The buyer would distinguish the increase from 35 feet to 40 feet and from two stories to three stories from any proposal for that particular parcel. Those district limits do not establish that a taller building will appear on the property. The buyer would ask the Planning Division which zoning district applies and how its standards relate to the development being considered.
What residential land use categories changed?
The ordinance lists employee housing and small residential care facilities as permitted uses in all RPD zones, while large residential care facilities require a conditional use permit.
The employee housing definition covers housing for six or fewer employees and treats it as a residential land use and a single-family structure. These are land use classifications.
For senior housing, the staff report says a conditional use permit is no longer required in RPD 14, 30, 30A, 50 and 80; it is permitted subject to a Planned Development Permit, with a reduced parking standard. The Senior Housing Overlay remains so the five existing sites do not become nonconforming.
The short version
Ordinance 26-363 changes specific development standards, so start with the parcel’s zoning and the project you actually have in mind.
Ask the Planning Division how the SB 9 criteria, replacement requirements or height limits apply. Keep questions about accessory dwelling units separate; ADU rules are another topic to review.
If you’re preparing to sell, start your pricing questions with the home value tool.
Common questions
Has Mission Viejo adopted Ordinance 26-363?
According to the city's meeting summary, the City Council adopted it on October 13, 2026. The ordinance says it takes effect 30 days after passage.
Does Ordinance 26-363 guarantee an SB 9 lot split?
No. The ordinance provides for staff review and approval using its criteria and standards. Ask the Planning Division how those requirements apply to the property.
Can a dwelling created under the SB 9 section be a short term rental?
The ordinance prohibits short term rentals for units created under that section and requires a minimum rental period of one month.
Which residential districts received height increases?
The changes cover RPD 30, RPD 50 and RPD 80, which are multifamily residential districts. The reports describe no height change in the single-family RPD 3.5 and RPD 6.5 districts.
