How we clean and match permits

Where the permits come from

We read the public building permit records of 23 permit offices in North Carolina: Mecklenburg County, Cabarrus County, Union County, Gaston County, Wake County, Raleigh, Durham, Cary, Morrisville, Apex, Wake Forest, Fuquay-Varina, Garner, Johnston County, Greensboro, Guilford County, High Point, Alamance County, New Hanover County, Brunswick County, City of Asheville, Onslow County and Cumberland County. Each comes from the office's own system: its open-data feed where it publishes one, and its public permit portal where it doesn't. We don't buy permit lists or leads, and the rest of the state isn't in the data, so our counts are never state totals.

A few portals show only part of their records. Apex, Fuquay-Varina and Wake Forest's search shows at most 50 permits of each type, so we hold only some of theirs.

How often it's checked

• Every office is checked for new and changed permits at least once a day; some every hour, some every 15 minutes.
• Permit Search and the Permit Map are rebuilt from those checks four times a day.
• The area, contractor, ZIP and trade pages are rebuilt every night, and each states the date its figures run through.

A permit can still reach us days after it's filed, because offices publish on their own schedule and some only once a permit is issued. The Help Center's office table shows each office's newest permit.

What we clean, and what we leave alone

Every office names its fields differently, so each record is mapped into one format: permit number, type, description, address, dates, status, declared value and contractor. The permit's own words stay on it. What we add on top:

• A stage. Each office's status words are sorted into seven stages, so "Ready for Issuance" in Raleigh and "Awaiting Payment" in Cabarrus County both read as Approved. A word we haven't checked goes in Other. Every status word and its stage.
• A kind of work. New build, addition, remodel, roofing, electrical and so on, read from the permit's type and description. How each permit is sorted.
• A map location. From the office's own map where it publishes one, otherwise from the address.

What we don't touch: the declared value is the applicant's figure, never adjusted. A permit with no city stays without one rather than getting a guess from its address. And a status is as of our last check, not a live feed.

Duplicates

Each permit is stored once per office, by its permit number. When an office changes a permit, a new status or an issue date, the same record is updated rather than a second one added.

Where a county's records also list permits that a city inside it issues, the copy is removed, so one permit counts once.

Several permits at one address aren't duplicates. A house usually has a building permit and separate electrical, plumbing and mechanical permits, each with its own contractor. More on permits at one address.

Matching contractor names

The same business is written many ways: "ABC Plumbing, Inc.", "A.B.C. PLUMBING INC", "ABC Plumbing LLC". For contractor pages and counts, names that differ only in spelling, punctuation or an ending like Inc or LLC count as one business. Names like Owner or N/A aren't a contractor, so they get no contractor page.

Nothing fuzzier than that is automatic. Two names that differ by more than spelling stay separate, because a wrong merge would put one company's permits on another's page. The exception is a short list of businesses that file under two names, such as a legal name and a trade name, each checked by hand before it's joined.

Where phone numbers and emails come from

First from the permit itself. Where the office doesn't publish a phone or email, we look it up in other official records, such as the office's own permit pages and the state licensing board, and use a result only when it matches exactly one contractor. A lookup that could be two businesses is skipped, not guessed.

Some offices publish no contractor at all, and a homeowner's own permit names none, so not every permit has a contractor or a phone. Which offices publish what.

If something looks wrong

A mistake in an office's record shows up here too, since we don't rewrite what a permit says. Email support@tarsignal.com with the permit number or the page, and we'll check it against the office's record.