Pasadena, CA Building Safety: Anti-Mansionization (2026)
Key Facts
- Base cap
- 35% above neighborhood median house size
- Neighborhood radius
- 500 ft around the property
- SCP, lots <12,000 sf
- 30% of lot size plus 500 sf
- SCP, 12,000-24,000 sf
- 20% of lot size plus 1,700 sf
- SCP, ≥24,000 sf
- 25% of lot size plus 1,000 sf
- Exempt additions
- Up to 500 sf, not visible from street
Summary
Pasadena limits new house size to 35 percent above the median home size within a 500-foot radius under its Single-Family Compatibility Permit program. Municipal Code Section 17.22.040 sets that base cap, and homeowners who want to exceed it must obtain the permit described in Section 17.22.050.E and 17.22.090.
The allowable floor area of houses shall not exceed 35% above the median house size of all properties within 500 foot radius of the subject property.(5) The 500-foot radius shall serve as the project's neighborhood for purposes of neighborhood compatibility. See Section 17.22.050.E for additional information regarding neighborhood compatibility calculation.(6)(7) Subject to approval of a Single-Family Compatibility Permit, the allowable floor area of the house may exceed 35% above neighborhood compatibility, up to the maximums specified below: Site less than 12,000 sf 30% of lot size plus 500 sf 35% of lot size plus 500 sf per unit Site of 12,000 sf to 24,000 sf 20% of lot size plus 1,700 sf Site 24,000 sf or more 25% of lot size plus 1,000 sf
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 79 Update 2).
Full Breakdown
040, which caps a new or expanded single-family house at 35 percent above the median house size of every property within a 500-foot radius, called the 'neighborhood' for compatibility purposes. E defines that radius precisely: it excludes properties outside Pasadena, properties in a different RS district than the subject site, and properties cut off by a significant manmade structure like a freeway or a significant natural feature like a canyon. 090, and Table 2-3 spells out the maximums available with that permit: 30 percent of lot size plus 500 square feet on lots under 12,000 square feet (35 percent of lot size plus 500 square feet per unit in RM-12), 20 percent of lot size plus 1,700 square feet on lots between 12,000 and 24,000 square feet, and 25 percent of lot size plus 1,000 square feet on lots of 24,000 square feet or more.
Certain floor area is excluded from the calculation altogether: habitable attic space under specific dormer and footprint limits, unenclosed areas that are mostly open on one or more sides, and basements, decks, balconies, and porches. Additions of up to 500 square feet are exempt from the neighborhood compatibility requirement entirely if they are not visible from a public right-of-way, letting owners add modest square footage without triggering the 500-foot radius review.
Violations & Fines
Floor area built beyond the neighborhood compatibility cap without an approved Single-Family Compatibility Permit is a Zoning Code violation and public nuisance under Section 17.78.060, exposing the owner to a Stop Work Order and administrative penalties under Chapters 1.25 and 1.26. Section 17.78.070 makes each day of the violation a separate offense, and a Single-Family Compatibility Permit already granted can be revoked under Section 17.78.090 if the review authority finds its conditions were violated or based on a misrepresentation.
Frequently Asked Questions
How much bigger than my neighbors' houses can I build in Pasadena?
What counts as my 'neighborhood' for the compatibility calculation?
Are small additions exempt from the compatibility limit?
What floor area can I get with a Single-Family Compatibility Permit on a 15,000-square-foot lot?
Sources & Official References
Other rules in Pasadena
California rules heatmap·Compare Pasadena to another location·View the California building safety overview
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