How much does it cost to build a house in Altadena?

A new 1,800 sq ft, 3-bedroom home costs about $873,000 to build, all in, including building, site work, city fees and design. Land is extra: about $701,250 for a typical lot in areas like Altadena.

What is a new home worth in Altadena?

About $1,912,500 for a new 1,800 sq ft home in an area like Altadena.

What a new home costs in Altadena (2026)

Building a new custom home, tearing down and rebuilding, or rebuilding after a fire in Altadena? Hemisphere A&E is an architecture and design-build firm: one team for design, permits and construction. Here are typical numbers, the local rules, and your next step.

Typical new home numbers in Altadena

A new 1,800 sq ft, 3-bedroom home costs about $873,000 to build, all in: building, site work, city fees and design. Land is extra.
Typical land value for a lot in areas like Altadena: about $701,250.
Finished value: about $1,912,500 (about $850 per sq ft plus a new-home premium).
A new home like this could rent for about $7,740 a month.

Run the free new home cost calculator for Altadena

Building permits and local rules in Altadena

Who runs permits

LA County Public Works (building permits, on EPIC-LA) and Regional Planning (zoning).

Fire rebuild help

For Eaton Fire rebuilds, the County offers pre-approved plans, a self-certification option, and fee deferrals or refunds for homes the owner lived in. There's a One-Stop Permit Center in Altadena.

What can slow you down

Much of Altadena is in a high fire zone. New homes there need fire-resistant building.
New state rules will ban burnable things within 5 ft of homes (Zone 0).
SB 9 lot splits are paused in the burn area for now.

Free lot check in Altadena

Send Hemisphere A&E your address. We look up your zoning and lot size, what fits (ADU, junior ADU, SB 9, new home, apartments, remodel or business space), red flags like fire zones or hillside rules, and a rough cost range. No cost, no pressure. Email info@hemisphereae.com or call (619) 762-7144.