In short
- Our figures come from public records: City of Los Angeles building permits for homes served by LADWP.
- Utility rules and rebates come from each utility's own pages, and every guide links its official sources.
- One set of rules builds every page, so a page's header numbers, summary and tables always agree.
- Installers can't pay to change any figure. Sponsored listings, if we sell them, are labeled and kept apart from the data.
Sources
| Source | Data through | Terms |
|---|---|---|
| Los Angeles Department of Building and Safety (LADBS) electrical permits | Sep 27, 2026 | City of Los Angeles open data (public records) |
| PVWatts v8 (National Laboratory of the Rockies) | Modeled | U.S. government |
| Census ZIP code centroids | 2020 | Public domain |
What counts as a solar install
We use the City of Los Angeles's electrical permits (LADBS) for 1-or-2-family homes flagged as solar, counted in the year the permit was issued. Revisions of an earlier permit aren't counted again. A permit means the work was approved, not that it was finished. The permits don't record installer names or prices.
Batteries
Batteries are found by keywords in the permit description (battery, energy storage, ESS, Powerwall), because the permits have no battery flag. A battery permitted with solar counts as "with a battery"; one added to an existing system, or installed alone, is counted separately as "battery-only".
Medians and small numbers
We show a median and the middle half (the range covering the middle 50% of permits) only when at least 20 permits are behind it; otherwise the page says "too few to say". We don't compare a year with one that had fewer than 20 permits, and changes under 5% read "about the same". The latest year is partial and labeled with the date the data reaches; only full years are compared.
Which places get a page
The City of Los Angeles has a page, and each neighborhood council area with at least 60 home solar permits has its own.
Production estimates
Yearly output per kilowatt comes from PVWatts for 19 reference points across Southern California (south-facing, 20° tilt, 14% system losses). Each area uses the nearest point. Real output depends on shade, roof direction and equipment.
Independence
SoCal Solar Tracker may sell clearly labeled sponsored listings to licensed installers. Payment never changes the data, or what a page says about any company, and sponsored listings always show the company's license number and a link to verify it.
Reuse
Our compilations of these records are free to reuse with credit. Free to reuse with credit to SoCal Solar Tracker (socalsolartracker.com), under CC BY 4.0.
Corrections
Found a number that looks wrong? Tell us and we'll check it against the source.