Methodology

Every number on this site traces back to a building permit issued by a city government. Here is exactly how we get from a raw filing to a published median.

1. Where the data comes from

We pull issued building permits directly from each city's official open-data portal. No intermediaries, no scraped aggregators.

City	Dataset
Austin, TX	City of Austin Development Services — Issued Construction Permits
Chicago, IL	City of Chicago Department of Buildings — Building Permits
Los Angeles, CA	City of Los Angeles Department of Building and Safety — Building Permits
San Francisco, CA	City and County of San Francisco DBI — Building Permits
New York, NY	NYC Department of Buildings — DOB NOW: Build Job Application Filings
Seattle, WA	City of Seattle SDCI — Building Permits
New Orleans, LA	City of New Orleans — Building Permit Applications
Montgomery County, MD	Montgomery County MD — Commercial and Residential Building Permits
Kansas City, MO	City of Kansas City MO — Issued Building Permits
Baton Rouge, LA	East Baton Rouge Parish — Building Permits
Marin County, CA	County of Marin — Building Permits
Everett, WA	City of Everett — Permits
Corona, CA	City of Corona — Building Permits
Anaheim, CA	City of Anaheim — Building Permits
Raleigh, NC	City of Raleigh — Building Permits
Detroit, MI	City of Detroit BSEED — Building Permits
Sacramento, CA	City of Sacramento — Issued Building Permits

2. How work is classified

Permits carry a free-text description written by the applicant — for example "Interior remodel to increase the size of the living room, kitchen and primary suite." We match that text against a keyword pattern for each project type. A permit that matches no pattern is discarded rather than guessed at.

3. Which values are excluded

Raw permit data contains obvious data-entry errors — we have seen a backyard pergola filed at $830,000,000. Each project type has a plausible floor and ceiling, and values outside it are dropped. We publish a distribution only when a city has at least 12 qualifying permits for that project type, and we report the median rather than the mean so a handful of very large jobs cannot distort the typical figure.

4. What a declared value is — and is not

The figure on a permit is the value the applicant declares to the city, usually for fee assessment. It is a real number attached to a real project at a real address, which is what makes it far more grounded than a survey estimate. But it has limits you should know:

It can sit below the final invoice, since change orders and finish upgrades often land after filing.
It typically covers construction work, not always appliances, furniture or design fees.
Unpermitted work never appears. Small jobs done without a permit are invisible here, which pushes the low end of the distribution up.

Treat these numbers as a well-grounded floor and a reliable guide to relative cost — between cities, between project types, and across the range from a modest job to an expensive one.

5. How often it updates

The pipeline re-reads every city's portal and rebuilds the site monthly. Each page shows the date of the data it was built from. This page was built 2026-09-04.