Contractors in Thornton, CO

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What the records show in Thornton

Our Colorado records put 1,789 contractors and tradespeople in Thornton, which places the city 7th statewide, 629 of them with a lapsed license. City license lists add the non-state trades: Aurora (116), Arvada (113) and Thornton (111) list Thornton-based contractors, which gives us 30 roofing licenses, 53 general contractor licenses and 46 HVAC/mechanical licenses.

64% of them show an active license on file, above the Colorado-wide figure of 54% for the profiles we hold. State licensing boards are the main source here: we count 1,178 electrical licenses (131 masters, 700 journeymen, 144 residential wiremen) and 485 plumbing licenses (103 masters, 245 journeymen) in Thornton. That is the 7th-largest electrical workforce in our Colorado data. Most entries are individual tradespeople (1,359), not companies. Only 80 active electrical contractor and 58 active plumbing contractor registrations are based here, and those are the businesses that can sell electrical or plumbing work to you directly.

49 profiles carry a state board discipline flag (27 electrical, 22 plumbing), and 30 of those licenses are still active. A flag can mean anything from a paperwork lapse to a serious finding, so read the board record behind it. The median first-license year is 2008. 546 records predate 2000, and 202 licenses were first issued in 2024 or later.

We matched 36 Thornton companies to Colorado Secretary of State filings: 19 in good standing and 17 delinquent or dissolved. A dissolved entity can't back a warranty, so check the status before you sign. Profiles cluster in ZIP codes 80229 (500), 80241 (420), 80233 (393), out of 13 ZIPs on file.

97 permits from City of Boulder and Denver open data trace back to 9 contractors based in Thornton. The leaders are Alliance Electric Solutions LLC (37), All Phases Of Remodeling (26), All Green Construction LLC (23). The newest is dated 2026-10-08, and at least 6 were issued in the past year. Most are electrical permit (39), sign permit (11), alteration/tenant finish (10). These are jobs these firms did in Boulder or Denver. Thornton doesn't publish permits in a portal we cover yet, so no permits shown doesn't mean no permits pulled.

Permit data: City and County of Denver Open Data Catalog, licensed under CC BY 3.0. HomeProFax matched permits to licensed contractors by name; data modified from the original. Not endorsed by the City and County of Denver.

HomeProFax profiles with a Thornton address, built from DORA electrical and plumbing rosters, the Aurora, Arvada and Thornton contractor license lists, Colorado Secretary of State filings and Boulder/Denver open permit data. Counts as of Oct 24, 2026.

Shortcut: before you hire, ask any Thornton contractor for their verified HomeProFax report. A contractor with a clean record can share it in a minute.

Thornton licensing rules, with sources

Local authority: City of Thornton Building Inspection Division. What we verified on official pages (Oct 2026):

• Thornton requires contractors to be licensed before a building permit is issued. Qualification is a current license from a reciprocal jurisdiction or an ICC certification for the class. (source)
• Electrical and plumbing contractors in Thornton also need valid Colorado state and master licenses. (source)
• Thornton issues one-year licenses through its CityView portal, and homeowners working on their own primary residence don't need a contractor license. (source)

Electricians and plumbers are also licensed statewide by the DORA State Electrical Board and the DORA State Plumbing Board. Rules and fees change, so confirm with the department before you sign.

Hail, roofs and your contract

Thornton sits on the Front Range, in the heart of "Hail Alley." The Rocky Mountain Insurance Information Association says the region usually sees three or four catastrophic hailstorms a year, and the damaging season runs from mid-April to mid-September. Eight of the twelve costliest Colorado hailstorms on RMIIA's list were centered on the Denver metro, led by the May 8, 2017 storm at $2.3 billion in insured losses. After a storm, Colorado law lets you cancel an insurance-paid roofing contract within 72 hours of a written claim denial (C.R.S. 6-22-104), and a roofer may not offer to pay or waive your deductible (C.R.S. 6-22-105).

Thornton contractor list

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Thornton contractor FAQ

How many Thornton contractors does HomeProFax track?

HomeProFax lists 1,789 contractor profiles with a Thornton business address. 1,148 (64%) show an active license on file and 629 show an expired one. 1,178 hold electrical licenses and 485 hold plumbing licenses.

Do contractors need a license in Thornton?

City of Thornton Building Inspection Division handles contractor licensing for Thornton. Thornton requires contractors to be licensed before a building permit is issued. Qualification is a current license from a reciprocal jurisdiction or an ICC certification for the class. Electricians and plumbers also need Colorado DORA licenses.

Have any Thornton contractors been disciplined?

49 Thornton profiles carry a Colorado state board discipline flag, and 30 of those licenses are still active. Open the profile and read the board record before you hire.

Which Thornton contractors have the most permits on file?

Alliance Electric Solutions LLC leads with 37 permits. In total, 9 Thornton-based contractors have 97 permits on file from the Boulder and Denver open-data portals HomeProFax covers.

Can I find licensed roofers based in Thornton?

Colorado has no state roofing license, so roofers come from city license lists. 30 roofing licenses (29 active) belong to Thornton-based contractors on the Aurora, Arvada and Thornton lists HomeProFax holds.

How do I verify a contractor in Thornton quickly?

Ask the contractor for their verified HomeProFax report. It puts their license status, any board discipline, permits on file and Secretary of State standing on one page with sources. You can also search any business free on HomeProFax.com.