Altadena

An unincorporated foothill community north of Pasadena.

Snapshot

Population

41,705

US Census ACS, 2024 / FBI UCR Table 8, 2024

Median home price

$1,576,457

Redfin, 2026-08

Median rent

$2,355/mo

US Census ACS, 2024

Crime / 1k

Data pending

Median sale price, year over year: +40.8% (rising)Redfin, 2026-08

Market

Price / sq ft

$755

Redfin, 2026-08

Months of supply

2.3

Redfin, 2026-08

Median days on market

41

Redfin, 2026-08

Renter-occupied

23.1%

US Census ACS, 2024

Median household income

$128,720

US Census ACS, 2024

Housing units

15,815

US Census ACS, 2024

Developments

What you can build here — ADU

LA County contractVHFHSZHCD Non-Compliance Flag

Unincorporated; LA County Title 22 controls. Typical SFR lot: 1 attached ADU + 1 detached ADU + 1 JADU. SB9 dual units allowed outside VHFHSZ and outside Eaton Fire boundaries (EO N-32-25). State 750 SQFT impact-fee and 500 SQFT school-fee exemptions apply. Ministerial ADU clock is 60 days; fire rebuild plan review goal <10 business days.

§22.140.640. Last verified 2026-08-18. Not legal advice — confirm current requirements with Altadena's planning department. See the statewide ADU floor every city sits on top of.

What you can build here — zoning standards

Zone(s)DensityHeightSetbacks F / S / RLot coverage
Single-familyR-1 (6,000–40,000 sf min by suffix)1 du/lot (~5–8.7 du/ac by suffix)30–35 ft / <2 stories20' avg (min) / 5–10' / 10–25'35–45%
DuplexR-22 units/lot (~14 du/ac)20–30 ft / 2 stories20' avg / 5–15' / 10–20'~40%
TownhomeR-3 / Planned residential~16–30 du/ac density-bonus eligible35 ft basePer zone (varies)Per zone
MultifamilyR-3~16–30 du/ac35 ft15' / per zone / per zonePer zone
R-4Higher density with overlays35+ ft with approvalPer zonePer zone

Parking · SFR 2 covered; Duplex 1.5 covered + 0.5 uncovered/unit; MF 1.5–2 covered + guest (varies).

Overlays to check · SB 9 lot-split eligible · Density Bonus Law applicable · Hillside Overlay · Historic Overlay · CSD overlays (Altadena CSD modifies R-1 yards/height)

Base zoning — always check for a project-specific overlay or density-bonus increase. Not legal advice. LA County Title 22 Ch 22.18 (base residential zones), Altadena CSD 22.306.070-A/B, DRP zoning summary. Last verified 2026-08-21. Full zoning code

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