Why the Palisades is shielded from speculative lot-splitting — and Altadena is left exposed. Fire Hazard Severity Zones, the fire disaster area (burn perimeter), and the SB 1090 ZIP areas (91001 / 91003), on one map.
Note: ZIP 91003 is a PO-box-only ZIP with no separate boundary; the SB 1090 Altadena area is shown by ZIP 91001. The Palisades sits almost entirely inside the Very High zone (shielded from SB 1123 and given SB 9 relief by executive order), while most of Altadena's burned residential core lies outside the Very High zone — so SB 1123 applies and the SB 9 relief does not.
Even with the by-right SB 9 and SB 1123 subdivision pathways paused, homeowners still have tools to add appropriate density. The County's ADU ordinance already lets a single lot hold up to four dwelling units — a primary home plus three accessory dwelling units — with no lot split required.
▸ LA County ADU Ordinance — Single-Family Home Guide (2026) · PDF
Sources: Fire Hazard Severity Zones — CAL FIRE (services.gis.ca.gov). Burn / recovery footprint — LA County, "Palisades and Eaton Dissolved Fire Perimeters" (as of 2025-01-21). ZIP boundaries — U.S. Census ZCTA. Basemap © CARTO, © OpenStreetMap contributors. Prepared by Altadena Recovery Watch.