Methodology and sources

Every fee, bond amount, threshold, experience requirement and renewal cycle on this site was read from an official source: a state licensing board, state statute or administrative code, a state open data portal, or the exam vendor a board contracts with.

Each one is shown with a link to that source, the date it was read, and a verbatim quote held in our data. When we could not find a value on an official source, the page says so instead of guessing.

How each state is built

• Who licenses what: we read the state board and agency sites for general, electrical, plumbing, HVAC and roofing work, and record the official license lookup for each trade. A lookup is marked checked only when we loaded it ourselves.
• Requirements: each exam, experience, bond, insurance, fee and renewal value is stored as a fact with its source link, a verbatim quote that contains the value, and the date we read it. Our build refuses any number that does not appear in its own quote.
• No state license: we say flatly that a state has no license for a trade only when an official source says so. Otherwise we say our survey found none and point you to the city or county.
• License counts: we use bulk data only where the publisher offers it as a download or open data feed and its terms allow reuse. We publish counts only, never names, addresses, phone numbers, emails or license numbers, and we leave out small groups.
• Every number on a state page must trace to that state's data file; an automated check fails the build otherwise.

License counts come from one or more official datasets per state. Each dataset is listed under the counts with its publisher, data license, attribution and the date the publisher last updated it. Some rows count businesses and others count individual license holders; each such row is labeled business, individual or mixed, and we never add business and individual rows together. A row with fewer than ten records is left out, so small groups never show.

We do not use third-party license directories, insurance or bond seller blogs, encyclopedias or AI answers as sources. To confirm a specific contractor, use the official lookup link on each state page.