Data sources
Every business in our directory traces back to one of these public registries or to an owner-submitted listing. We never invent rows. Each section below explains what the source is, exactly which records we pull, and how often we refresh.
Illinois IDPH Licensed Plumber registry
State or local licensing authorityWhat it is. The Illinois Department of Public Health (IDPH) licenses every plumber working in Illinois under the Illinois Plumbing License Law (225 ILCS 320). Plumbing is regulated as a public-health matter -- to protect the potable water supply -- so IDPH, not a contractor board, holds the statewide license roster. Each active license carries the plumber's name, license number, and license type (apprentice, journeyman, or licensed plumber).
How we use it. We import active IDPH-licensed plumbers and tag them with source_name='IL IDPH' so they can be filtered or removed in bulk if the licensing relationship ever changes. Cert chips on each profile name the specific IDPH license type held.
Refresh cadence. Re-pulled quarterly; on-demand when a license lapses.
Citation: Illinois IDPH Plumbing Program (dph.illinois.gov)
City of Chicago plumber licenses
State or local licensing authorityWhat it is. The City of Chicago licenses and bonds plumbers and plumbing contractors working within city limits, separately from the statewide IDPH license. Chicago's licensed-contractor records are public information published by the Department of Buildings.
How we use it. Imported as company-level rows with source_name='Chicago'. Geographic scope is the City of Chicago; statewide IL coverage flows through IL IDPH. Cert chips name the City of Chicago plumber license.
Refresh cadence. Re-pulled quarterly.
Citation: City of Chicago Dept. of Buildings (chicago.gov)
Chicago Data Portal business licenses
State or local licensing authorityWhat it is. The City of Chicago's open-data portal publishes active business licenses -- including plumbing contractors -- through a public Socrata API. Records include the legal and doing-business-as name, address, and current license status.
How we use it. Pulled live from the Socrata endpoint filtered to plumbing-related license codes with status = ACTIVE. Tagged with source_name='Chicago Data Portal' and deduped against the City of Chicago license list by name + address.
Refresh cadence. Re-pulled weekly.
Citation: Chicago Data Portal (data.cityofchicago.org)
PHCC of Illinois member directory
Professional associationWhat it is. The Plumbing-Heating-Cooling Contractors Association of Illinois (PHCC of Illinois) is the state's leading plumbing trade association. Its public member directory lists member firms that invest in apprenticeship, training, and code-compliance standards.
How we use it. Member firms are matched against listings we already have and tagged with the 'PHCC Member' credential. We do not auto-create listings from association membership alone.
Refresh cadence. Re-pulled quarterly.
Citation: PHCC of Illinois (ilphcc.com)
Illinois Secretary of State business registry
State or local licensing authorityWhat it is. The Illinois Secretary of State publishes the public business-entity database -- corporations and LLCs registered to do business in Illinois, with formation date and good-standing status.
How we use it. Used during verification to confirm a claimed plumbing business is a registered Illinois entity in good standing. We do not import listings from this source; it is a cross-check only.
Refresh cadence. Checked at verification time.
Citation: Illinois Secretary of State Business Services (ilsos.gov)
Want to see our verification process step-by-step? Read How we verify. For our editorial neutrality, dispute, and removal policies, read Trust standards.
If you represent one of these registries and have feedback on how we cite or use your data, please contact us.