You go to an in-network hospital for surgery. Everything looks fine on paper. Then, weeks later, you get a bill from the anesthesiologist for $4,200, someone you never chose, never met outside the OR, and had no idea was out-of-network. That is balance billing, and as of 2022 (enforced into 2026 and beyond), it is federally illegal in that exact scenario.
Quick Answer: Balance billing is when an out-of-network provider charges you the difference between what your insurer paid and the provider's full rate. The federal No Surprises Act (in effect since January 1, 2022) bans balance billing for emergency care, for out-of-network providers at in-network facilities, and for air ambulance services. Ground ambulances and elective out-of-network care are the two main gaps where balance billing can still legally happen as of 2026.
Understanding where the law protects you, and where it does not, is the fastest way to know whether a bill you received is something you actually owe or something you can challenge.
What Balance Billing Actually Means
When you see a doctor who participates in your health plan's network, that provider has agreed to accept the insurer's contracted rate as payment in full. If your insurer pays $800 toward a $1,000 charge and the negotiated rate is $800, you owe only your cost-sharing (copay, deductible, coinsurance), not the $200 gap.
Out-of-network providers have no such contract. They can bill your insurer at any rate, receive a partial payment (or nothing), and then send you a bill for the remainder. That remainder is called the "balance." Billing you for it is balance billing.
Common situations where it showed up before the No Surprises Act:
- An out-of-network ER physician treating you at an in-network hospital
- An out-of-network radiologist reading your in-network MRI
- An out-of-network anesthesiologist assigned to your in-network procedure
- Air ambulance transport to a hospital
The 2026 federal rules have closed most of those gaps. But not all of them.
The No Surprises Act: What It Covers in 2026
The No Surprises Act (NSA), part of the Consolidated Appropriations Act of 2021, took effect January 1, 2022, and its protections remain fully in force for plan years starting in 2026. According to CMS.gov, the law bans balance billing in three main categories:
1. Emergency Services
If you receive emergency care from an out-of-network provider or facility, that provider cannot balance bill you, regardless of whether you had any choice in the matter. You pay only your normal in-network cost-sharing (copay, deductible, coinsurance).
This applies to:
- Emergency room visits
- Stabilization care after an emergency
- Any related services during an emergency admission
2. Out-of-Network Providers at In-Network Facilities
This is the scenario described at the top: the out-of-network anesthesiologist, radiologist, or assistant surgeon assigned to your in-network procedure. The NSA bans balance billing for "ancillary" services provided by out-of-network providers at in-network hospitals and surgery centers.
Ancillary services include: anesthesiology, radiology, pathology, emergency medicine, neonatology, and surgical or medical assistance services. Providers cannot charge you more than your in-network cost-sharing for these.
3. Air Ambulance Services
Out-of-network air ambulance providers are prohibited from balance billing you. You pay in-network cost-sharing only.
The gap: ground ambulances. Ground ambulance services are explicitly excluded from the No Surprises Act. As of 2026, federal law still allows ground ambulance providers to balance bill patients. According to the Commonwealth Fund, 22 states have enacted some ground ambulance protections for fully-insured plans, but self-funded employer plans (which cover most private-sector workers) remain unprotected even under state laws.
When Balance Billing Is Still Legal in 2026
The NSA does not ban all balance billing. Providers can still balance bill you in these situations:
Scheduled out-of-network care with written consent. If you voluntarily choose an out-of-network provider for non-emergency services and the provider gives you a written notice explaining the lack of NSA protection, and you sign a consent form, the provider can balance bill you. This is called the "notice and consent" exception.
Ground ambulance. As described above, federal law has no prohibition here. Check your state's rules, but coverage is inconsistent.
Out-of-network facilities. If you go to a hospital or surgery center that is entirely out of network, the NSA protections for ancillary providers do not apply (because the facility itself was not in-network to begin with).
Balance billing is always legal for the uninsured. The NSA is a health insurance regulation. If you paid cash or had no insurance, the law's balance billing prohibitions do not apply, though separate "good faith estimate" rules do require providers to give you upfront price estimates.
Good Faith Estimates: A Related Protection
Starting in 2022, uninsured and self-pay patients can request a Good Faith Estimate from any provider before scheduled care. The estimate must list expected charges for all providers involved in a procedure, including out-of-network ones. If your final bill exceeds the estimate by more than $400, you can dispute it through the Patient-Provider Dispute Resolution (PPDR) process managed by CMS.
For insured patients, the NSA also requires that providers give advance notice when they know an out-of-network provider will be involved in your care, so you can request an in-network alternative.
How to Spot a Balance Bill You Should Not Owe
Look for these signals on any hospital or provider bill:
- The bill is from a provider you did not separately choose (anesthesiologist, ER doctor, radiologist)
- The care was emergency or at an in-network hospital
- The bill references an "out-of-network" charge or "patient responsibility" after your insurance paid
- The amount is unusually large and does not match your plan's cost-sharing structure
If any of those match, run the charges through the CoveredUSA Bill Analyzer before paying anything. The CoveredUSA Bill Analyzer compares each line on your Explanation of Benefits to standard rates and flags charges that may violate NSA protections or represent billing errors, in about 30 seconds.
How to Dispute a Balance Bill: Step-by-Step for 2026
If you believe a provider balance billed you illegally, here is how to fight it.
Documents you will need:
- The itemized bill from the provider
- Your Explanation of Benefits (EOB) from your insurer
- Any consent forms you signed (or did not sign)
- Records of the date of service and the facility name
- Any prior authorization approvals from your insurer
Step 1: Call your insurer first.
Ask your health plan to confirm whether the service is covered under the NSA and whether they already paid the provider. Sometimes the insurer underpaid and the provider is legitimately pursuing the balance from you, which is allowed. Other times, the insurer paid correctly and the provider should not be billing you at all.
Step 2: Contact the provider's billing department.
Tell them the service was subject to NSA protections and ask them to reprocess the bill. Reference the specific protection: emergency services, or ancillary care at an in-network facility. Get the representative's name and note the date.
Step 3: File a complaint with CMS if the provider refuses.
The No Surprises Help Desk at 1-800-985-3059 accepts complaints in English, Spanish, and over 350 other languages. You can also submit online at CMS.gov's medical bill rights portal. CMS can refer your complaint to the appropriate federal or state agency for enforcement.
Step 4: Use the Patient-Provider Dispute Resolution process (for uninsured patients).
If you are uninsured and your bill exceeds your Good Faith Estimate by more than $400, initiate the PPDR process through CMS. An independent third party reviews the charges and determines a fair payment.
Step 5: Contact your state insurance commissioner.
Many states have additional surprise billing protections on top of the NSA, and state law may cover situations federal law misses. Your state insurance commissioner's office is the right agency to contact for state-regulated plans.
Common reasons disputes are denied:
- You signed a valid notice and consent form waiving NSA protections
- The facility was out-of-network (not just the provider)
- The care was non-emergency and scheduled with an out-of-network provider you chose
- The service occurred before January 1, 2022
State-Level Protections That Go Further in 2026
The NSA is a federal floor, not a ceiling. States can enact stronger protections and many have. As of 2026, states with notable additional balance billing laws include:
- New Hampshire: Balance billing for ground ambulances became illegal starting January 1, 2026, covering both emergency and non-emergency services for state-regulated plans.
- Washington: State rules extend surprise billing protections to ground ambulance services for fully-insured plans.
- New York, California, Texas, Illinois: All enacted surprise billing laws before the federal NSA and maintain stronger protections in some areas.
The critical limitation: state laws cannot bind self-funded ERISA employer plans. If you get insurance through a large employer that self-funds its health benefits (common at companies with 500+ employees), only federal NSA protections apply, not state laws.
Check with your state's department of insurance to find out whether additional protections apply to your specific plan type.
The Independent Dispute Resolution Process (For Providers and Plans)
When a provider and an insurer disagree about what the NSA requires the insurer to pay, they go through Independent Dispute Resolution (IDR), a separate process from consumer complaints. This is a business-to-business arbitration process that you as a patient do not participate in, but it matters because a favorable IDR decision for the insurer means the provider cannot pass extra costs to you.
According to CMS, both sides submit payment offers and evidence to a certified IDR entity, which selects one of the two offers. In 2026, CMS is transitioning the IDR system to a new "IDR Gateway" platform for better case management.
As a patient, you do not file IDR cases. But if a provider tells you they are "in arbitration" with your insurer and therefore you owe the balance, that is not accurate. You are not responsible for the balance while IDR is pending.
What the CoveredUSA Bill Analyzer Looks For
Upload your hospital or provider bill to the free CoveredUSA Bill Analyzer to find errors, overcharges, and charity care options in 30 seconds. The analyzer specifically flags:
- Charges that appear to violate NSA balance billing rules
- Duplicate billing codes on the same itemized bill
- Charges above Medicare reference rates (a common signal of overcharging)
- Services that may qualify for financial assistance or charity care at the same facility
Knowing exactly which line items are problematic before you call the billing department puts you in a much stronger position to negotiate or dispute.
Frequently Asked Questions
What is balance billing in simple terms?
Balance billing is when a healthcare provider charges you the difference between their full rate and what your insurance paid. For example, if a provider bills $3,000, your insurer pays $1,500, and the provider then sends you a bill for the remaining $1,500, that is balance billing.
Is balance billing illegal in the United States as of 2026?
It depends on the situation. Federal law (the No Surprises Act) bans balance billing for emergency services, for out-of-network ancillary providers at in-network facilities, and for air ambulances. It does not ban balance billing for ground ambulances, for out-of-network facilities, or for elective care where you signed a consent form waiving protections. Some states have additional bans that go further.
Can a hospital send me to collections for a balance bill I dispute?
Providers are supposed to pause collection activity while a complaint or dispute is under review with CMS. If a provider continues collection efforts or reports the balance to credit bureaus during an open dispute, that may itself be a violation worth reporting. The CFPB and CMS both handle complaints about NSA violations.
Does the No Surprises Act apply to Medicare and Medicaid patients?
Medicare and Medicaid have their own, separate balance billing rules. Medicare has long prohibited participating providers from billing Medicare patients more than the Medicare-approved amount. The NSA primarily addresses private health insurance plans. Medicaid balance billing rules vary by state. If you are on Medicare or Medicaid, contact your plan or the relevant agency directly.
What is the difference between a surprise bill and balance billing?
"Surprise bill" is the broader colloquial term for any unexpected medical bill. Balance billing is the specific mechanism: charging you the difference between the provider's full rate and the insurance payment. Not all surprise bills are balance bills. A surprise bill could also be a bill for a service you did not expect, or a bill that turns out to be a billing error rather than an intentional charge.
How do I know if my employer plan is self-funded (and whether state laws apply)?
Ask your HR department or look at your Summary Plan Description (SPD). If your plan is self-funded (also called self-insured), it is governed by federal ERISA law, and state surprise billing laws do not apply. Only the federal NSA protections cover you. Self-funded plans are common at companies with 500 or more employees and are also called "administrative services only" (ASO) plans.
What if I already paid a balance bill that was illegal?
You can still file a complaint with CMS and may be entitled to a refund. Contact the No Surprises Help Desk at 1-800-985-3059. Keep records of the payment and any bills or EOBs related to the service. CMS can investigate and require the provider to refund amounts collected in violation of the NSA.
Can I check whether a specific charge on my bill is a balance billing violation?
Yes. Upload your itemized bill or Explanation of Benefits to the CoveredUSA Bill Analyzer at coveredusa.org/medical-bill-analyzer. It cross-references charges against reference rates and flags potential NSA violations for you to investigate or dispute.
