IOP & PHP Billing Codes for Behavioral Health

How IOP and PHP claims are structured

Intensive outpatient programs (IOP) and partial hospitalization programs (PHP) deliver several hours of structured treatment a day while the patient lives at home. Most payers pay them as a daily (per diem) rate rather than visit by visit, which is why the IOP billing codes look different from the psychotherapy codes a therapist uses.

How a program bills depends on how it is licensed and enrolled. A facility enrolled as a hospital outpatient department or community mental health center usually bills on the institutional claim (UB-04/837I) with revenue codes. A licensed freestanding program may bill per diem HCPCS codes on either form, depending on the payer. Confirm the claim form and codes in each payer contract before the first admission.

For outpatient psychotherapy codes used alongside or after a program, see the behavioral health billing guide.

Core IOP billing codes and PHP codes

Code	Descriptor (summary)	Common use
H0015	Alcohol and/or drug services; intensive outpatient (program operating at least 3 hours/day and at least 3 days/week, based on an individualized treatment plan), including assessment, counseling, crisis intervention and activity therapies or education	SUD intensive outpatient, per day of service
S9480	Intensive outpatient psychiatric services, per diem	Mental health IOP for commercial payers that accept S codes
H0035	Mental health partial hospitalization, treatment, less than 24 hours	Mental health PHP, mainly Medicaid
S0201	Partial hospitalization services, less than 24 hours, per diem	PHP for some commercial payers
H2036	Alcohol and/or other drug treatment program, per diem	SUD program per diem for some Medicaid plans

HCPCS Level II H codes are used mainly by Medicaid and state behavioral health programs, while S codes are used by some commercial payers. Medicare does not pay H or S codes. A payer that does not recognize one of these codes will deny the claim, so check each payer's code list rather than assuming.

H0015 billing and S9480 billing in practice

For H0015 billing, the descriptor sets a minimum program structure: at least three hours a day, at least three days a week, under an individualized treatment plan. Document start and stop times for each group and individual session so the daily hours can be shown. Days that fall short of the program minimum may not support the per diem; follow the payer's policy for partial days.

S9480 billing follows the same per diem logic for psychiatric IOP. Many commercial contracts pair S9480 with a revenue code on an institutional claim and specify a minimum number of hours or services per day.

• Bill one unit per day of service unless the contract defines units differently.
• Match the diagnosis to the program: SUD diagnoses (F10-F19) for H0015, mental health diagnoses for S9480.
• Track authorized days and the level-of-care review dates; most IOP authorizations are short and need concurrent review.
• Do not bill individual psychotherapy codes for services already included in the per diem unless the contract allows it.

Revenue codes for facility IOP and PHP claims

Revenue code	Description
0905	Intensive outpatient services, psychiatric
0906	Intensive outpatient services, chemical dependency
0912	Partial hospitalization, less intensive
0913	Partial hospitalization, intensive

Commercial and Medicaid facility claims often pair these revenue codes with a per diem HCPCS code, such as 0906 with H0015 or 0905 with S9480. Your contract decides which pairing is accepted. Payers may also require a specific type of bill and an attending provider NPI on each claim.

Group therapy inside a Medicare PHP or IOP is reported with HCPCS G0410 (group psychotherapy other than a multiple-family group, in a partial hospitalization or intensive outpatient setting, approximately 45 to 50 minutes) or G0411 (interactive group psychotherapy in the same settings).

Medicare intensive outpatient coverage since 2024

Starting January 1, 2024, Medicare began covering intensive outpatient program services in hospital outpatient departments, community mental health centers, federally qualified health centers and rural health clinics, following the Consolidated Appropriations Act, 2023. Opioid treatment programs can also furnish IOP services for opioid use disorder.

• Hospital and CMHC IOP claims carry condition code 92; PHP claims carry condition code 41.
• A physician must certify that the patient needs at least 9 hours of IOP services per week; PHP requires a need for at least 20 hours per week.
• Services are billed line by line with HCPCS codes for each service, and Medicare pays a per diem based on the number of services furnished that day.
• FQHCs and RHCs follow their own IOP billing instructions in CMS MLN Matters articles.

Medicare does not use H0015 or S9480. Programs serving both Medicare and commercial patients need two billing setups for the same clinical service.

SUD billing codes and detox billing codes

Substance use treatment uses a family of HCPCS H codes, mainly for Medicaid and state-funded programs. These SUD billing codes describe assessment, counseling and withdrawal management at different levels of care.

Code	Description (summary)
H0001	Alcohol and/or drug assessment
H0004	Behavioral health counseling and therapy, per 15 minutes
H0005	Alcohol and/or drug services; group counseling by a clinician
H0012	Alcohol and/or drug services; sub-acute detoxification (residential addiction program outpatient)
H0013	Alcohol and/or drug services; acute detoxification (residential addiction program outpatient)
H0014	Alcohol and/or drug services; ambulatory detoxification
H0020	Alcohol and/or drug services; methadone administration and/or service

The detox billing codes run from H0008 through H0014 and are split by setting (hospital inpatient, residential, outpatient) and by acute or sub-acute intensity. Most outpatient programs use H0014 for ambulatory withdrawal management. State Medicaid manuals define units and documentation, such as withdrawal scale scores, for each code.

42 CFR Part 2 billing and consent rules

Federally assisted SUD programs must follow 42 CFR Part 2, which protects SUD treatment records more tightly than HIPAA. Unlike HIPAA, Part 2 requires written patient consent before records are disclosed for payment, so 42 CFR Part 2 billing starts with a valid consent form at intake.

The 2024 final rule aligned Part 2 more closely with HIPAA. Programs had until February 16, 2026 to comply. Key changes include:

• A single consent can cover all future uses and disclosures for treatment, payment and health care operations.
• HIPAA covered entities and business associates that receive records under that consent may redisclose them as HIPAA permits, with limits on use in legal proceedings against the patient.
• SUD counseling notes need a separate consent that cannot be combined with other consents.
• Breach notification follows the HIPAA breach rules, and patients have new rights to complaints and accountings of disclosures.

If a patient refuses consent to bill insurance, the program cannot send the claim. Record the refusal and set up self-pay. A billing company working for a Part 2 program needs a business associate or qualified service organization agreement before handling records.

Billing support for IOP, PHP and SUD programs

Fastora's certified coders set up payer-specific per diem and revenue code rules, track authorized days and check Part 2 consent before claims go out. Learn about our substance use treatment billing and eligibility verification services, or request a free billing assessment of your program claims.

Frequently asked questions