California Medical Billing Laws 2026: Provider Guide

California medical billing laws include the California False Claims Act (CFCA), the Knox-Keene Act, AB 72 surprise billing rules, and state-specific timely-filing requirements.  Each of them is enforced by a different agency. 

This guide explains the California Medical Billing laws in 2026 that apply to your practice. Become aware about the deadlines that carry the highest financial risks and billing mistakes that can lead to audit and investigations. 

What California Medical Billing Laws Apply to Your Practice

California providers don’t just follow one set of billing rules. State law covers Medi-Cal claims. While federal law covers Medicare. And for the practices that bills both? The same coding error can trigger both at once. 

State laws vs. federal laws 

California providers face two separate layers of billing law depending on which program they bill. 

• The California False Claims Act (Gov. Code §§ 12650–12656) governs Medi-Cal claims. 
• The federal False Claims Act (31 U.S.C. §§ 3729–3733) governs Medicare 

So, if your practice bills both programs it can face simultaneous investigations from state and federal authorities for the same coding error. 

However, patient privacy laws are a different concern as they operate under HIPAA and California`s Confidentiality of Medical Information Act (CMIA). This act protects patient information during billing. If your practice works with outside billing staff, California`s HIPAA and CMIA requirements explain how to keep patient information safe and secure. 

Agencies that enforce California billing rules

There are five different agencies that oversee different parts of medical billing in California. For example:

• Department of Health Care Services (DHCS) handles Medi-Cal billing compliance.
• The California DMHC oversees health plans and HMOs covered by the Knox-Keene Act. 
• The California Department of Insurance regulates commercial insurers. 
• CMS, OIG, and DOJ enforce federal rules related to Medicare billing.
• The California Attorney General can take action against providers that violate the California False Claims Act when they bill state programs. 

California Patient Billing Rights Providers Must Follow

California law gives patients their specific billing rights that providers are responsible to honor. If they violate them, even without a coding error, it still results in compliance complaints and patient disputes. 

Itemized billing statement requirements

California patients can ask for an itemized bill, and providers must provide it. It needs to show the date of service, a description of what was done, the CPT or procedure code, and the charge for each service.

This is a simple requirement, but missing information can create an avoidable compliance problem. 

AB 72 surprise billing protections

AB 72 protects patients from unexpected out-of-network bills in certain situations. If a patient gets non-emergency care from an out-of-network provider at an in-network facility, the patient generally pays only their normal in-network cost.

The billing risk for providers is network status. A claim processed as out-of-network when the provider is in-network triggers an AB 72 violation even if the procedure code is correct. Verify network status before submitting, not after a patient complaint arrives. 

SB 1061 and medical debt credit reporting (2025)

SB 1061 restricts the reporting of medical debt to consumer credit reporting agencies. Under Civil Code §1785.27, a person generally may not furnish information about a medical debt to a consumer credit reporting agency.

Since July 1, 2025, new medical debt agreements must tell patients that their debt cannot be reported to credit bureaus. Providers should review the bills of their patients, payment plans, and collection letters to make sure they follow these rules. 

Medical Billing Time Limits in California

Filing deadlines run independently of fraud liability. If you submit a claim too late, the insurer may deny it, and the practice may lose the chance to get paid. Practices that catch upcoding or unbundling errors weeks after submissions have limited time for correction. 

Medi-Cal timely filing limits

For Medi-Cal fee-for-service claims, original claims generally must be received within six months following the month in which the services were provided. DHCS refers to this as the six-month billing limit. This is not simply a 180-day countdown from the date of service.

For example, if the date of service is April 15, the claim generally must be received by the end of October to meet the six-month billing limit. Certain exceptions may apply when an approved delay reason supports late submission.

Providers should also distinguish Medi-Cal fee-for-service billing rules from Medi-Cal managed care requirements. DHCS notes that the six-month FFS billing limit should not be used as the rule for managed care plans with capitated arrangements.

AB 118, effective January 1, 2024, raised Medi-Cal reimbursement for primary care, OB, and outpatient mental health to 87.5% of the Medicare fee schedule. Missing a deadline on these claims now costs more per claim than it did before the rate increase 

Medicare and Medicare Advantage filing windows

Medicare claims generally must be submitted within 12 months of the date of service. If you need to correct a claim, the 12-month deadline still starts from the original date of service, not from the date you find the mistake.

Medicare Advantage plans have different rules. Each plan may set its own filing deadline, so providers should check the plan’s contract before submitting a claim.

Commercial payer deadlines and California’s prompt pay interest rule

Commercial insurance plans usually give 90-180 days for submissions. The exact deadline depends on the payer’s contract. So, billing teams should check the rules of each plan. 

California also has a prompt pay rule for insurers. Once an insurer receives a clean claim. They generally pay an electronic claim within 30 days and a paper claim within 45 days. 

If the insurer fails to pay within the required time, it may owe 15% annual interest on the overdue amount. 

Workers’ compensation billing deadlines in California

Workers’ compensation claims have their own deadlines. Generally, initial claims should be submitted within 12 months of the date of service. 

If you disagree with a payment decision, you generally have 90 days from receiving the Explanation of Review to request an Independent Bill Review. Some cases, like cumulative trauma or emergency services, may have different deadlines. 

Workers’ comp liens may be filed up to five years from the date of service under Cal. Labor Code §4603.2. 

California Medical Billing Time Limits at a Glance

The table below summarizes filing deadlines and payment timelines by payer including the late payment penalty California law imposes on commercial insurers. 

California Medical Billing and Coding Requirements

Medi-Cal has coding and authorization requirements that differ from Medicare. A claim can be submitted on time with correct procedure codes and still be denied, because a required prior authorization was missing or the fee schedule was outdated. 

Medi-Cal coding rules and prior authorization requirements

Some Medi-Cal services need approval before you can bill them. This approval may come through a Treatment Authorization Request (TAR) or Service Authorization Request (SAR). 

Reimbursement rates are a separate risk. AB 118, effective January 1, 2024, raised Medi-Cal reimbursement for primary care, OB, and outpatient mental health to 87.5% of the Medicare fee schedule. 

Practices using outdated fee schedules may submit claims at incorrect amounts. It creates overpayment liability when DHCS identifies the discrepancy during reconciliation. 

If the required approval is missing, Medi-Cal may deny the claim even when the billing codes are accurate. Medi-Cal billing rules can also change, so check the latest DHCS Medical provider resources before submitting an unfamiliar claim. 

AB 72 billing accuracy and out-of-network coding risks

Incorrectly processing a claim as out-of-network can create a compliance problem when California’s surprise-billing protections apply. Fixing a network status error after a patient complaint is too late. 

If a claim is incorrectly processed as out-of-network when the provider is in-network, it triggers an AB 72 violation even if the procedure code is correct. Verify network status and confirm your billing system reflects current provider contracts before submitting 

NCCI edits and unbundling compliance

NCCI edits identify CPT code pairs that must be billed together rather than separately. Submitting them as separate charges is unbundling and carries CFCA liability regardless of intent. 

For a full breakdown of how unbundling violations occur and what penalties apply, see our guide to upcoding and unbundling in California.

California False Claims Act and Billing Fraud Laws

The California False Claims Act imposes some of the highest financial penalties per false claim plus treble damages. It’s three times the government’s total loss. It applies to any entity that knowingly submits false claims to Medi-Cal or other state-funded programs. . 

What the CFCA covers and who it applies to

Under Government Code §§ 12650–12656, the CFCA applies to entities that submit false or fraudulent claims under government programs, including Medi-Cal. Liability applies when a provider knowingly submits a false claim. 

The law also allows qui tam lawsuits, where employees such as billing staff or coders can report fraud on the state’s behalf. If the government recovers money, the whistleblower receives 15–30% of the total recovery. 

Penalties under the CFCA and federal FCA

The CFCA can impose civil penalties of $5,500–$11,000 per false claim with treble damage. The federal False Claims Act (FCA) also allows treble damages and per-claim penalties at $13,946-$27,894. Criminal prosecution under 18 U.S.C. §1347 carries up to 10 years imprisonment and fines up to $250,000 for individuals. 

The consequences can go beyond fines. A fraud finding may lead to exclusion from Medicare or Medi-Cal, loss of payer contracts, or professional licensing action.

California has pursued cases involving routine billing errors and medically unnecessary services. For example, in 2021, the California Attorney General announced a $3.31 million settlement with SuperCare Health over allegations involving Medicare and Medi-Cal billing for ventilator services that were no longer medically necessary.

Knox-Keene Act Requirements for Managed Care Billing

The Knox-Keene Act is California’s managed care law. It sets rules on how HMO health plans licensed by the DMHC must handle claims. It includes payment timelines, clean claim standards, and disputes acknowledgment windows. 

Clean claim standards and HMO payment timelines

Under the Knox-Keene Act, DMHC-regulated HMO plans must pay clean electronic claims within 30 days, and paper claims within 45 working days. Disputed claims must be acknowledged within 15 working days.

A claim with coding errors, upcoding, or unbundling may not qualify as a clean claim. This can affect payment timelines and may cost you late-payment penalties.

What DMHC enforcement looks like for providers

DMHC mainly regulates health plans, not providers. However, a plan audit can uncover provider billing problems, leading to overpayment recovery or further review by DHCS. 

Providers can also challenge improper claim denials. If a plan fails to pay a clean claim on time, providers can file a complaint with DMHC. 

How to Keep Your California Practice Billing Compliant

California billing compliance starts with catching problems before claims are submitted, not after a denial or audit. 

Internal billing compliance checklist

Start by checking each payer’s timely filing deadline before submitting a claim, since Medi-Cal and commercial payers may have different requirements. Run NCCI edits on CPT code pairs and confirm that any required Medi-Cal TAR or SAR authorization is in place before billing.

Review E/M coding patterns quarterly, especially the frequency of Level 4 and Level 5 codes, to spot unusual patterns that may attract payer scrutiny. Also, update fee schedules when DHCS changes Medi-Cal reimbursement guidance and verify network status for claims that may fall under AB 72 protections.

When to bring in external billing support

Most practices don’t catch the filing deadline or NCCI edit internally, especially small offices that don’t have a dedicated compliance role. A virtual medical biller can review claims against NCCI edits and check other billing requirements before submissions. 

Practices with high Medi-Cal volumes can use medical insurance virtual assistants to track authorization requirements and payer deadlines across a large volume of claims. 

It’s also worth understanding how virtual staff can support revenue cycle management before deciding where your billing process needs support.

If your practice has changed EHR systems, added providers, or never had a formal coding review, schedule a billing compliance review before the next denial or audit finds the gap first. 

The Right Billing Process Protects Your Practice 

California’s billing rules don’t pause while your team catches up. Practices that wait for a denial or an audit notice to find the gaps usually find them at the worst time.

If you don’t have a dedicated compliance process in place, that’s the gap worth closing first.

Talk to our team about what that looks like for your practice.