Our methods
Know what’s behind the numbers.
Public records can make planning easier, provided their limits are clear. Here is how we turn those records into local project guides.
Method documented
Sources you can check
- Housing Element Annual Progress Report (APR) Data by Jurisdiction and Year
ADU units permitted and completed per city and year (Table A2), every LA County jurisdiction.
- Building Permits Issued 2020 to Present (data.lacity.org dataset pi9x-tg5x)
City of Los Angeles building permits: last-12-month counts, median days to permit and median declared valuation, as aggregates only.
- LADBS mechanical permits (data.lacity.org dataset 67is-svtd)
City of Los Angeles HVAC permit counts, as aggregates only.
- American Community Survey 5-year estimates
Housing age, ownership and home values per city (5-year estimates with margins of error).
City and county figures are different
California HCD’s annual reports provide city-level ADU activity across Los Angeles County. LADBS building and mechanical records cover the City of Los Angeles. A City of LA valuation shown on another city’s guide is regional context, not a local estimate.
Missing records are not treated as zero. Sources can have different reporting periods, and recent annual reports may be revised. Each figure keeps its source and data date.
Permit value is not your project price
Our cost tool uses declared valuations from issued permits. These are amounts recorded in permit applications, not verified contractor quotes or final bills. The middle-half range runs from the 25th to the 75th percentile; its midpoint marker is the median.
The data importer suppresses counts with fewer than five underlying records and medians with fewer than 20. ZIP-level figures are shown only where the source and sample support them. A missing ZIP result should not be replaced with a claim about your neighborhood.
How we prepare the data
We calculate aggregates from the public datasets using service-specific filters. Building-permit filters and mechanical-permit filters are separate. Permit counts, permitted housing units and completed units are different measures and are labeled accordingly.
Service valuation and timing series use the project and property-type filters described with each figure. Where stated, fire-rebuild records are excluded. These filters reduce misleading comparisons but do not make every project in a series identical.
Census housing figures are survey estimates. They describe the broader housing stock, not demand for a specific service or the condition of an individual home.
How guides are written and checked
Our publishing process uses templates and AI-assisted drafting with automated checks for sourced numbers, links and page structure. A publication date does not imply that a licensed professional reviewed a guide.
Separately checked city instructions link to the responsible department and show a check date. Other planning information is general guidance. The relevant city department decides which rules and permits apply to your property.
“Updated” reflects a recorded content change; it does not roll forward automatically with the calendar. A data date describes the underlying records and can be older than the page.
Referrals and independence
Contractors may pay us for qualifying leads. That commercial relationship does not turn a dataset’s median into a quote, or a referral into an independent contractor ranking. Read about our service.