What the No Surprises Act Covers, and What It Leaves Out

Search the full text of 45 CFR Part 149 — the rules that carry out the No Surprises Act — for the words ground ambulance. They are not in it. Not as a definition, not as an exception, not as a cross-reference. Air ambulance has a section to itself. The vehicle that takes most people to an emergency room has nothing.

That gap is the shape of the whole law in one detail, and it is why two bills from the same night can look identical and land on opposite sides of it. The emergency physicians group bills $1,940 after insurance. The county ambulance service that drove you eight miles to that same emergency room bills $1,286. You chose neither provider. Federal law makes one of those balances unlawful to charge you and leaves the other as an ordinary out-of-network bill.

So the sentence everybody repeats — that the law protects you from surprise bills — is true and close to useless at the moment you are holding paper. The protection is not drawn around unfairness. It is drawn around three specific situations, and a bill either lands inside one of them or it does not. Every rule below was read against the eCFR text of Part 149 on 19 August 2026 (title 45 current through the 17 August 2026 issue date) and linked, so none of it has to be taken on trust. Not a lawyer, not a biller.

The three doors

Everything the federal law does for a person with insurance runs through one of these.

Emergency services. Your plan has to cover them without prior authorization, whether or not the provider or facility is in network, and it cannot impose cost sharing greater than an in-network visit would have carried (45 CFR 149.110(b)). The provider and the facility are separately barred from billing you the rest (149.410(a)).

Non-emergency care from an out-of-network provider at an in-network facility. The anesthesiologist who was not in your network, at the hospital that was. Cost sharing comes down to the in-network level on the plan's side (149.120(c)), and the provider is barred from sending you the balance (149.420(a)).

Air ambulance. If your plan covers air ambulance at all, it must cover an out-of-network one at in-network cost sharing, calculated as though the charge were the lesser of the qualifying payment amount or the billed amount (149.130(b)(2)), and the air ambulance provider is separately barred from billing you the difference (149.440(a)).

There is a fourth piece of Part 149 that has nothing to do with your insurance. If you are uninsured or paying cash, providers owe you a good faith estimate. Total billed charges that land at least $400 above that provider's estimate are "substantially in excess," which is the phrase that makes the bill eligible for a federal dispute process, and the notice starting it has to be postmarked within 120 calendar days of that first bill (149.620(a)(2)(ii), (b) and (c)(1)). While the dispute is pending the provider must not move the bill into collections, and late fees have to stop accruing (149.620(c)(5)). Different door, different paperwork, and it is worth a page of its own.

One detail to mark on your own statements: cost sharing charged under these rules counts toward your in-network deductible and in-network out-of-pocket maximum, not the out-of-network ones (149.110(b)(3)(v), 149.120(c)(5), 149.130(b)(3)). Plans get this wrong. It is the kind of error that never appears as a denial and shows up only as a deductible that refuses to move.

"Emergency" here is wider than the waiting room

The test is the prudent layperson standard, and it turns on how the condition looked to you, not on what the workup eventually found. An emergency medical condition is one manifesting acute symptoms, including severe pain, of sufficient severity that a prudent layperson with average knowledge of health and medicine could reasonably expect that going without immediate attention would place health in serious jeopardy or cause serious impairment to bodily functions or serious dysfunction of a bodily organ or part (149.110(c)(1)). Mental health conditions and substance use disorders are named in that definition. And a plan may not limit what counts as an emergency medical condition on the basis of diagnosis codes alone (149.110(b)(4)) — the provision to quote when a discharge diagnosis of "gastritis" is being used to reclassify the chest pain you arrived with.

Emergency services then cover the medical screening examination and the treatment needed to stabilize you, and they keep going after that. Items and services furnished once you are stabilized, as part of observation or an inpatient or outpatient stay on that same visit, are still emergency services (149.110(c)(2)(ii)). A hospital can strip that post-stabilization protection off only if every condition in 149.410(b) is met. That list opens with a determination by the attending emergency physician or treating provider that you are able to travel by nonmedical or non-emergency medical transportation to an available participating provider within a reasonable travel distance, and it runs through your being in a condition to receive the information and give informed consent at all, plus any additional requirements state law imposes.

An independent freestanding emergency department counts, so long as it is geographically separate and distinct and licensed separately from a hospital under state law (149.30).

The word doing the most work is "facility"

For the non-emergency protection, "health care facility" is not a general term. It is a closed list of four, at 45 CFR 149.30: a hospital, a hospital outpatient department, a critical access hospital, and an ambulatory surgical center.

Read that list twice, because a great many bills that feel like surprises come from places that are not on it. The freestanding imaging center. The independent pathology lab. The urgent care storefront. The specialist's own office. An out-of-network bill from any of those may be unfair, badly disclosed, and still entirely lawful under Part 149.

Inside the four, the reach is longer than people expect. A "visit" includes equipment and devices, telemedicine services, imaging services, laboratory services, and preoperative and postoperative services, regardless of whether the provider furnishing them is at the facility (149.30). The pathologist who read your slide in another county, on that visit, is inside the rule. That wording has stood since the 2021 interim final rule, and it is worth being clear about what the recent change to the same section did: the June 2026 rule (91 FR 34070, 4 June 2026) added a definition of bundled payment arrangement and left visit alone.

Where the protection actually stops

Ground ambulance. Not in the statute, not in Part 149. Congress ordered up the Advisory Committee on Ground Ambulance and Patient Billing instead, and CMS records the sequence on the committee's own page: charter signed 16 November 2021, three public meetings across 2023, a report to the Secretaries issued 28 August 2024, and a status today of inactive. A recommendation is not a rule. What exists now is state law, and the Commonwealth Fund's map of state ambulance protections counts 24 states with some version of it, for people enrolled in fully insured plans. Which means the funding question decides whether any of it reaches you at all, and that is a separate piece of homework: Self-Funded or Fully Insured? How to Find Out for Sure.

A valid notice and consent. This is the exception that swallows bills, and it is also the one providers most often botch. The paragraphs are arranged in a way that invites the mistake: 149.420(a) sets out the prohibition and then adds "unless the provider ... satisfies the notice and consent criteria," which makes a signature look like the end of the question. Paragraph (b) is the one to read first. The consent route is simply unavailable — the provider stays barred from balance billing you no matter what you signed — for the ancillary services listed at (b)(1): emergency medicine, anesthesiology, pathology, radiology and neonatology; assistant surgeons, hospitalists and intensivists; diagnostic services including radiology and laboratory; and anything from a nonparticipating provider when no participating provider at that facility can furnish it. A second clause, (b)(2), does the same for items and services furnished as a result of unforeseen, urgent medical needs that arise at the time (149.420(b)).

If the service falls outside those two clauses, the consent still has to have been executed properly. HHS publishes the form itself — Standard Notice and Consent Documents Under the No Surprises Act, OMB control number 0938-1401, the page you would have signed headed Surprise Billing Protection Form — and 149.420(c) through (h) sets the conditions around it. The notice comes with the consent document, physically separate and not attached to or incorporated into any other document. The timing has three cases rather than one: at least 72 hours before the service when the appointment was scheduled that far ahead; on the day the appointment is made when it was booked inside 72 hours; and never later than 3 hours before the service when the notice is handed over the same day.

What goes on the pages is prescribed too. The notice carries a good faith estimate of what the provider may charge, and says plainly that consenting is optional and that you may instead seek care from an available participating provider (149.420(d)). The consent form records the date and time you received the notice and the date and time you signed, and it has to tell you outright that what you pay may not count toward your in-network deductible or out-of-pocket maximum (149.420(e)) — a line worth rereading, since that is the protection being signed away. Language has its own paragraph: the documents must be offered in any of the 15 most common languages in the state, or in the region the facility serves, and an interpreter is required if yours is not among them (149.420(f)). A signed copy goes back to you, and whoever took the consent keeps it for 7 years, facility or provider (149.420(h)). So can you.

Your own out-of-network choice, away from those four facility types. Choosing an out-of-network surgeon for a scheduled operation at an out-of-network surgery center is not a surprise bill. That is the network working as designed.

Certain kinds of coverage. Subparts B, D, E, F and H do not apply to excepted benefits, short-term limited-duration insurance, or health reimbursement arrangements and other account-based group health plans (149.20(b)). If the card in your wallet is a short-term policy, the federal surprise billing rules are not yours to invoke.

Sorting the two bills

Work in this order, and write the answers down before you call anyone.

1. Where was the service furnished? An emergency department or independent freestanding ED, or one of the four facility types, or somewhere else. Somewhere else usually ends the federal analysis.
2. Was the facility in network and the provider out of network? Pull the EOB and check the network status for each rendering provider separately, not for the claim as a whole.
3. Is the service inside 149.420(b)? If it is, no consent form waived anything, and you can say so in one sentence.
4. If it is not, ask the provider in writing for the signed notice and consent document, with the recorded times on it. Somebody is required to still have it — the facility if the facility took the consent, the provider otherwise, seven years either way. Ask for the itemized bill in the same letter, using the wording that actually produces line items: Requesting an Itemized Bill: The Exact Words to Use.
5. Compare the cost sharing against your in-network numbers, including which deductible the amount landed on.

If it looks like a violation, the No Surprises Help Desk is 1-800-985-3059 and complaints go in at cms.gov/medical-bill-rights/help/submit-a-complaint. HHS will acknowledge receipt no later than 60 business days after it arrives, and may investigate, hand you to a state regulator, or refer the plan or provider for enforcement (149.150(b), 149.450(b)).

Keep one distinction straight while you wait. A complaint is about the billing rules. It does not touch a coverage decision, so if the plan also said the care was not covered, that denial is running its own clock on a separate track: Internal Appeal vs External Review: Which Track You're On. Two processes, two calendars. Open both this week, and put the ambulance bill in the state pile, where it belongs.