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Illinois Scale Certification & Weights and Measures

✓ Verified from official sources — July 11, 2026

Illinois runs a state-managed weights and measures program — commercial scale owners deal with the state agency directly. If you operate a commercial scale in Illinois — at a warehouse, farm, recycling yard, retail store, or truck stop — here is who regulates it, what the law requires, and exactly who to contact.

Who inspects commercial scales in Illinois?

State-run: 25+ state field inspectors perform regular unannounced inspections statewide (billed per the published fee schedule); cities of 25,000+ may appoint a city sealer who certifies devices locally.

What Illinois requires of scale owners

Devices must be placed in service by a licensed Registered Serviceperson (anyone selling, installing, servicing, or repairing devices must register with IDOA) and pass periodic state inspection.

Devices used to buy or sell by weight must comply with NIST Handbook 44 — in practice this means an NTEP-certified, legal-for-trade scale. Confirm requirements for your device class with the office listed here.

Getting a scale into service — 4 steps

  1. Buy a legal-for-trade (NTEP-certified) scale appropriate for your application and capacity.
  2. Confirm registration and licensing requirements with the Illinois Department of Agriculture ((217) 785-8301) before the scale enters commercial use.
  3. Arrange compliant installation and calibration. Where required, placing-in-service must be done by a licensed or registered service company.
  4. Stay compliant. Pass required inspections, keep calibration current, retain service records.

Common questions

Who certifies commercial scales in Illinois?
State-run: 25+ state field inspectors perform regular unannounced inspections statewide (billed per the published fee schedule); cities of 25,000+ may appoint a city sealer who certifies devices locally.
What does Illinois require of scale owners?
Devices must be placed in service by a licensed Registered Serviceperson (anyone selling, installing, servicing, or repairing devices must register with IDOA) and pass periodic state inspection.
What is NTEP certification?
NTEP certifies that a scale model meets NIST Handbook 44 standards for commercial use. An NTEP Certificate of Conformance is the standard requirement for legal-for-trade devices across the U.S.
Where do I find official forms and fees?
Use the licensing and forms links in the office panel, or contact the office directly — fee schedules change and some are published only in application documents.

Need calibration, repair, or installation in Illinois?

Send one request — ScaleRegistry routes it to qualified service providers for your state.

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