If you plan to start a wash–dry–fold (WDF) business and charge customers by the pound, the scale you use is regulated under U.S. weights‑and‑measures laws. The short version: whenever weight determines price, you must use a legal‑for‑trade, NTEP‑certified scale and have it inspected by your local authority.
1. Why scales are regulated in WDF services
In nearly every U.S. state, devices used in “commercial applications” are subject to regulation. NIST explains that a commercial application includes any situation where a scale is used to establish quantity for something offered for sale or hire—exactly what happens when you bill laundry by weight. These rules are compiled in NIST Handbook 44, which most states adopt as their technical standard.
Key idea: if weight → price, the scale must meet trade requirements.
2. What “legal‑for‑trade” and “NTEP‑certified” mean
A “legal‑for‑trade” scale is one that complies with NIST Handbook 44 and has been evaluated through the National Type Evaluation Program (NTEP). NTEP certification is administered by the National Conference on Weights and Measures (NCWM) and verifies that the model meets accuracy, construction, and security requirements for commercial use. You’ll typically see an NTEP Certificate of Conformance number or a “Legal for Trade / NTEP” marking on compliant scales.
Laundry scale vendors routinely highlight this point for WDF operators: if you weigh laundry to charge per pound, the scale must be NTEP‑approved.
3. Practical compliance requirements
Using an NTEP model is necessary but not always sufficient. Local weights‑and‑measures agencies usually require these steps:
- Buy an NTEP‑certified scale appropriate to your volume.
Look for explicit NTEP/Legal‑for‑Trade labeling and a Certificate of Conformance.
- Get the scale inspected and sealed before first use.
Inspectors verify accuracy and apply a seal or mark indicating the device is approved for trade.
- Expect periodic re‑inspections.
Re‑inspection intervals vary—often annually or biennially—and you may pay a fee.
Handbook 44 also sets expectations for day‑to‑day use, such as stable readings, appropriate display resolution, and tare capability so you can subtract basket weight.
4. Illinois and Chicago notes
Because you’re in the America/Chicago region, it’s worth calling out local practice:
- Illinois’ Department of Agriculture Bureau of Weights and Measures enforces commercial measurement standards statewide and follows the national NIST/NCWM framework.
- In the City of Chicago, the Department of Business Affairs and Consumer Protection (BACP) inspects and seals scales. Its published fee schedule lists a $25 certification fee per scale up to 24,000 lb capacity, plus a $100 re‑inspection fee if a device fails.
If you operate outside Chicago city limits, your county or state office typically handles inspection instead, but the legal‑for‑trade/NTEP requirement remains the same.
5. When you do NOT need a legal‑for‑trade scale
You only need a trade‑approved scale when weight affects what the customer pays. If you price differently—flat rates per bag, per item, or subscriptions not tied to measured weight—you may use any reliable scale internally, but you shouldn’t compute bills from a non‑trade weight.
6. Suggested scale features for WDF operations
While laws focus on accuracy and certification, WDF workflows benefit from a few practical features:
- Capacity in the 50–100 lb range for typical customer batches.
- A sturdy basket or platform that matches your sorting bins.
- Easy tare (zero) button for baskets and bags.
- Clear digital display; dual displays can reduce disputes.
These don’t change legality, but they make compliance and customer trust easier.
Conclusion
For a wash–dry–fold business that charges per pound, you should treat the scale as a regulated commercial measuring device: buy an NTEP‑certified legal‑for‑trade model, have it inspected and sealed by your local authority (BACP in Chicago), and keep it available for periodic re‑checks. Doing this early avoids fines, billing disputes, and reputation damage.
Sources
- NIST, *Handbook 44 – Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices* (current edition and PDF).
- NIST Office of Weights and Measures, “Weighing and Scales FAQs” (definition of commercial applications).
- Florida Dept. of Agriculture & Consumer Services, “What constitutes a legal‑for‑trade scale?” (clear definition tying NTEP + Handbook 44).
- Michelli Weighing & Measurement, “What is a Legal‑For‑Trade Scale?” (overview of NTEP/NCWM process).
- City of Chicago BACP, “Weights and Measures” page and certification application (inspection/sealing requirement and fee schedule).
- Laundry scale vendor guidance noting NTEP requirement for WDF per‑pound billing.