A charger that bills by the minute looks harmless: the driver pays for time, you collect revenue. The national model rule says that is not how electricity as a vehicle fuel is supposed to be sold. This article separates what is settled from what depends on your state, so you can set up billing before an inspector asks. It is not legal advice, and the pricing strategy side lives in Pricing Commercial EV Charging.
What is settled
NIST's guidance on EV fueling says electricity sold as a vehicle fuel is sold by the kilowatt-hour; NIST's materials also describe the megajoule as an allowed unit under the Handbook 130 model method-of-sale regulation. We did not read the exact Handbook 130 section. A charger cannot sell energy by units of time. You can, however, charge an additional fee for the time a vehicle occupies the space it needs to connect, such as an overstay fee once charging ends. NIST's answer is yes, provided the fee is properly disclosed, and the model text, as excerpted, expects those fees to be displayed and to appear on signs or advertising where they apply. Equipment that does both jobs has to keep the energy charge and the time charge clearly separate.
The equipment standard sits in NIST Handbook 44, section 3.40, which was a tentative code for years before it became a permanent code effective January 1, 2023 (per NIST materials seen in search results).
In plain terms: kWh for the energy, a separately labeled fee for time. A "per-minute" rate that is really the price of the electricity is the part that does not fit the model rule.
What depends on your state
Handbook 44 is a model, not federal law. NIST and the National Conference on Weights and Measures publish it, and each state decides whether to adopt it, which edition, and how hard to enforce. That is why you hear conflicting answers from vendors, who sell nationally.
The division of labor is also worth knowing. In most states, charger manufacturers are responsible for submitting models for National Type Evaluation Program (NTEP) certification. You, the owner, carry the state's installation and operation requirements: reporting the device, keeping it in service, and displaying prices correctly. So "is my hardware certified" is a question for your vendor; "have I told the state and priced correctly" is yours.
What we could confirm for four states:
| State | What the sources say | What we could not confirm |
|---|
| California | Regulation 4 CCR section 4002.11 applies Handbook 44 section 3.40 with state changes. A computing EV charger must display a unit price in whole cents or tenths of a cent per kWh or per megajoule, or show that charging is free. DC chargers installed on or after January 1, 2023 and AC chargers installed on or after January 1, 2021 must comply on installation. Older DC units have until January 1, 2033; the Division of Measurement Standards' notice D-23-01, as excerpted, treats AC units installed before January 1, 2021 but placed in service after it as exempt until January 1, 2031, with the DC equivalent running to 2033. | The exact answer in the Division's March 26, 2026 Q&A on whether a charger may bill by time alone. |
| Wisconsin | Wisconsin Act 121 (2023) removed chargers that bill by the kWh from the "public utility" definition, which brought them under the state's weights-and-measures law. Rule CR 25-034 would amend ATCP 92 to adopt the 2024 Handbook 44, including section 3.40. A January 29, 2026 department memo described the rule as final draft. | Whether the rule has been approved, cleared legislative review, and taken effect. Check the Wisconsin Administrative Register. |
| New York | The Bureau of Weights and Measures publishes an EV charger notification form (WM-15v, revised October 2024), so owners are expected to notify the state. | Whether and how the state requires NTEP certification, and its Handbook 44 adoption status. Call the Bureau at 518-457-3146 or email agr.sm.WeightsandMeasures@agriculture.ny.gov. |
| Maryland, Vermont | Maryland requires a placed-in-service report for new or repaired devices and logs location, network, make, model, serial number and AC or DC type. Vermont applies NTEP and Handbook 44 to some private chargers offered to the public through apps. | Detailed pricing rules in either state. |
California is the only state above where we could list specific install-date cohorts. The practical lesson from the other rows is that registration and inspection programs are spreading even where the pricing rule is not yet written down.
The per-minute question
Some vendors say pure per-minute billing avoids certified-meter rules because no energy is being "sold." We did not find a regulator that says so. NIST's guidance, as excerpted, describes selling energy by units of time as not allowed, with a separate disclosed fee for time in the space. Vendor pages say the same, but a vendor's reading is not a regulator's, and we could not open NIST's page itself. Treat per-minute energy pricing as unproven in your state until the state office tells you otherwise in writing.
The limits of what we read: we could not read the California Division of Measurement Standards' March 2026 answer on time-only billing, and we found no state list of who has adopted section 3.40. If you are in a state not covered above, assume nothing and ask.
What to do before launch
- Price energy in kWh. Put any time-based charge on its own line, labeled as parking, overstay or idle, and say when it starts.
- Post the price where the driver sees it. NIST's model text expects additional fees on signs or advertising. California requires a displayed unit price on newer units. Your network software usually controls the on-screen part; ask the vendor how it shows both lines.
- Ask your vendor for the certificate, not the claim. Request the NTEP certificate of conformance number for the exact model you are buying, plus any state-specific approval, and put it in the purchase contract. Commissioning and handover is the point to collect it.
- Call your state weights-and-measures office. Ask three questions: Is Handbook 44 section 3.40 adopted? Do I register or report each charger? Is a time-based energy rate allowed? Write down the name and date.
- Check the software. Confirm the platform can bill kWh plus a separate time fee and can show both on the receipt. See Software Platforms for Commercial Charging.
- If a provider operates the site for you, find out who holds the registration and the pricing risk; the contract terms are covered in Own, Operate, or Turnkey?. If tenants are being billed, the separate resale question is in Charging Tenants for EV Electricity.
Leaving this to chance has a cost on both sides: a charger that cannot lawfully bill is a charger that earns nothing until it is fixed. For how pricing choices feed payback, see DC Fast Charging ROI.
Where we could not confirm
nist.gov, cdfa.ca.gov and chargepoint.com did not resolve from our research environment, so we read NIST's EV fueling guidance, the California regulation and notices, and the Wisconsin rulemaking record only through search-result excerpts, not the full documents. The California Division of Measurement Standards March 2026 Q&A, the New York form's contents and NTEP requirement, Wisconsin's final rule status, and any state-by-state adoption list are unconfirmed. Treat the table as a starting point and confirm the current text with your state office.
Last checked: November 9, 2026, against search excerpts of NIST's Electric Vehicle Fueling FAQs and Handbook 44 section 3.40 materials, the California Division of Measurement Standards EVSE regulation and notice D-23-01, the Wisconsin DATCP rulemaking record for CR 25-034 and 2023 Wisconsin Act 121, the New York Bureau of Weights and Measures EVSE notification form, and Maryland and Vermont agriculture department EV charger pages. The primary documents were not opened directly; see the section above, and confirm the current text with your state office.
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