H0035: mental health partial hospitalization, treatment, less than 24 hours

The H0035 description

Phrase	What it tells you	What it leaves to the payer
Mental health	Written for psychiatric PHP. Many payers accept it for substance use PHP too (below).	Whether your program type and license qualify.
Partial hospitalization	The most intensive outpatient level: a structured day program for clients who'd otherwise need, or are stepping down from, inpatient care. ASAM Level 2.5 for substance use.	The admission and continued-stay criteria.
Treatment	Active treatment on a plan, not a drop-in or support service.	Which services count, and how many.
Less than 24 hours	The client goes home. It's outpatient.	The minimum hours that make a day, the unit and the weekly days.

Compare S0201, "partial hospitalization services, less than 24 hours, per diem": same idea, but the unit is written in, and it isn't limited to mental health. Payers that use S0201 are mostly commercial; H0035 is the H code many Medicaid programs and some commercial plans use.

Units: is H0035 a per diem code?

In practice, usually. The descriptor names no unit, so each payer sets one, and the ones that publish it mostly say one unit per day. Nevada Medicaid, for example, limited H0035 to one unit per day and no more than five units in seven rolling days. "How many units can you bill for H0035" therefore has two answers: one per date of service, and no more days than the authorization and the payer's weekly limit allow.

• One line per date, one unit. A week of PHP is five lines, not one line with five units.
• The day has to qualify. Payers commonly define a PHP day as 4 to 6 hours or more; some split a less intensive day (0912) from an intensive one (0913). The per diem billing guide lists published thresholds.
• Hourly exceptions exist. A few plans pay day treatment by the hour on a different code (such as H2012). If your contract says H0035 per hour, write it into your billing policy and check it on every claim.

Outpatient or inpatient? Place of service

H0035 is outpatient: "less than 24 hours" means the client doesn't stay overnight. On a facility claim (UB-04), it's an outpatient bill type, not an inpatient one; UB-04 vs CMS-1500 covers the type of bill. On a professional claim (CMS-1500), the CMS place of service code set has a code for exactly this: 52, psychiatric facility-partial hospitalization. A certified community mental health center uses 53. Some payers want a different POS in the contract; follow it.

Revenue codes 0912 and 0913

On a UB-04, PHP lines use revenue code 0912 (partial hospitalization, less intensive) or 0913 (partial hospitalization, intensive). Which one goes with H0035 is not settled nationally; payers disagree:

Payer	H0035 pairing	Source
Superior HealthPlan (Texas Medicaid)	H0035 with 0912 (less intensive); S0201 with 0913 (intensive). HCPCS required, revenue code optional.	Superior, September 2025
TRICARE	0912 with H0035 (or alone) for a half day; 0913 with H0037 (or alone) for a full day; one line per date.	TRICARE For Life
A Medicaid plan in another state	Splits the tiers by hours: 0912 for a less intensive day of 3 to 5 hours, 0913 for an intensive day of 6 or more. The HCPCS code then follows the tier the documented hours reach.	CareSource fee schedule
Your contract	The only pairing that counts for your claims.	Its billing exhibit or the plan's manual

The practical rule: if a payer splits half and full days, schedule and document so each day clearly lands in one tier, and set the revenue code from documented hours, not the schedule. Medicare uses other revenue codes for PHP line items (below).

H0035 for a substance use PHP

The descriptor says "mental health," but many payers accept H0035 for a substance use PHP (ASAM Level 2.5, which the 4th edition of the ASAM Criteria calls high-intensity outpatient), and others want S0201. Superior's Texas Medicaid mapping lists H0035 and S0201 for PHP without splitting mental health from substance use. Three checks before you bill H0035 for SUD:

• The contract names the code for your substance use PHP level.
• The license fits. In Texas, substance use treatment, including a substance use PHP, needs an HHSC chemical dependency treatment facility license (the CDTF license guide); a mental health PHP raises a different licensing question (licensing a mental health IOP or PHP).
• The criteria match. Payers review substance use PHP against the ASAM Criteria; our ASAM Criteria cheat sheet summarizes Level 2.5 and the dimensions behind it.

H0035 and Medicare

Medicare doesn't pay H0035: the CMS file lists it with coverage code I. Medicare does cover partial hospitalization, through a different structure:

	Commercial or Medicaid H0035	Medicare PHP
Who can bill	Programs the plan contracts with	Hospital outpatient departments and certified community mental health centers only
How the day is coded	One H0035 line per day	Each service on its own line with its own code, such as psychotherapy and group psychotherapy in a PHP or IOP setting (G0410, G0411); hospitals add condition code 41 (Claims Processing Manual, chapter 4)
How it's paid	The contract's per diem	An OPPS per diem for days with 3 services or 4 or more; CMHCs at their own lower rates
Hours and certification	The contract's definition	A client who needs at least 20 hours a week of therapeutic services, certified by a physician and recertified as of the 18th day, then at least every 30 days (42 CFR 410.43, 42 CFR 424.24)

Medicare's PHP coverage rules sit in the Benefit Policy Manual, chapter 6, the regulations above and your Medicare contractor's local guidance; none of them use H0035. A freestanding program licensed only by the state isn't a Medicare PHP provider type, so it can't bill Medicare for the day. The current per diems are explained in PHP reimbursement, and the provider-type rules in Medicare coverage of IOP and PHP. Medicare Advantage plans may contract differently; ask each one in writing.

H0035 and Texas Medicaid (TMHP and the plans)

• Adults: PHP reaches Texas Medicaid mainly as an in-lieu-of service: HHSC lets managed care plans offer it in place of inpatient psychiatric care (Uniform Managed Care Manual 16.3). A plan isn't required to offer it, and a member can't be required to use it.
• Under 21: PHP may be available through Texas Health Steps (EPSDT).
• Codes: HHSC asked plans to report PHP and IOP by HCPCS code, matching fee-for-service Medicaid. Superior lists H0035 (with optional 0912) and S0201 (with optional 0913), and has denied PHP claims without the HCPCS code since July 1, 2025.
• Authorization: plans require prior authorization before the first day; Superior wants requests at least five business days ahead. Details in Texas Medicaid for IOP and PHP programs.
• TMHP lookup: to see whether fee-for-service Medicaid lists a fee for H0035 for your provider type, use TMHP's Online Fee Lookup; our Texas Medicaid fee schedule guide walks through it. The plan rate is in each plan contract.

H0035 vs S0201, H0037, H2036 and 90853

Code	What it is	Unit	When it's used instead of H0035
S0201	Partial hospitalization services, less than 24 hours, per diem	Day	The contract names it, usually commercial; Superior uses it for the intensive PHP tier (0913).
H0037	Community psychiatric supportive treatment program, per diem (HCPCS.codes)	Day	TRICARE pairs it with 0913 for a full PHP day. Otherwise only where a manual names it.
H2036	Alcohol and/or other drug treatment program, per diem	Day	A Medicaid manual or contract uses it for a substance use level. It names no hours or level.
H0015 / S9480	Substance use / mental health intensive outpatient	Day	The client is authorized for IOP, the level below PHP. The code changes on the step-down date.
90853	CPT group psychotherapy (other than a multiple-family group)	Session	Outpatient clients, session by session. Inside an H0035 day the groups are already paid; billing 90853 on top is a duplicate.
G0410	Group psychotherapy in a PHP or IOP setting, about 45 to 50 minutes	Session	Medicare PHP and IOP line items at hospitals and CMHCs. Not a commercial per diem code.

A PHP day billed as H0035

A made-up adult client, Client C, in a mental health PHP. A made-up contract: H0035, one unit per day of at least 5 documented hours, UB-04, 0913 for days of 6 hours or more and 0912 for shorter qualifying days.

Time	Service	Hours
9:00–10:30	Process group, own entry, plan goal 1	1.5
10:45–12:00	Skills group (distress tolerance), own entry, goal 2	1.25
12:00–12:30	Lunch	0 (not a service)
12:30–2:00	Psychoeducation group, own entry, goal 3	1.5
2:00–2:45	Individual session with the primary therapist	0.75
Total	Four services, all signed that day	5.0: billable, 1 unit, 0912 (under 6 hours)

If this contract paid individual sessions separately, the 45 minutes would come off the day's hours (4.25), and the day would no longer qualify. That trade-off is why the contract's definition matters more than the code.

H0035 documentation requirements

• An admission assessment showing the client needs PHP now (risk, symptoms, function), against the plan's criteria; for substance use, the ASAM dimensions placing the client at Level 2.5.
• Physician or psychiatric involvement the contract requires: an evaluation, orders or periodic review. Medicare requires physician certification; many commercial plans want a psychiatric evaluation early in the stay.
• An individualized treatment plan, signed, reviewed on schedule (the treatment plan guide).
• A signed note per service with start and end times and the client's own entry (group therapy notes), adding up to the day's hours.
• Safety documentation: screening scores, risk assessments and a safety plan where indicated; PHP clients are often stepping down from inpatient care.
• An authorization for the date and level, and continued-stay reviews; PHP is usually authorized in short blocks (continued-stay documentation).
• Level changes in writing: in a Texas chemical dependency treatment facility, moving a client from PHP to IOP needs a signed decision with the rationale and effective date, a revised plan and coordination with the receiving level (26 TAC §564.804).

H0035 in Cima

Cima's Program plan for IOP and PHP sets the PHP level to S0201 by default, at 4 hours a day and 20 a week; switch it to H0035 under Settings, Program, set the hours your contracts require, and add up to four modifiers. A client-day becomes one unit of H0035 only when signed notes reach the day's hours, and the attendance screen shows the week against the weekly hours. Facility claims carry one revenue code per level (default 0913 for PHP); if a payer splits 0912 and 0913 by hours, tell us before you go live, because the code is set per level, not per day or per payer. PHP, IOP and outpatient are levels on one chart, so a step-down changes the code from that date without a new chart.

See Cima for IOP and PHP programs or compare the plans. Adding PHP to an IOP? Cima Consulting's guide to adding a level of care covers the license and payer steps, and billing set-up is $2,950, flat.

Questions

What is H0035?

A HCPCS Level II code for mental health partial hospitalization, treatment, less than 24 hours: one PHP day, usually billed as one unit. Medicaid programs and many commercial plans use it.

Is H0035 a CPT code?

No. It's a HCPCS Level II code from CMS. CPT codes, such as 90853, are the AMA's Level I codes.

Is H0035 a per diem code?

The descriptor doesn't say per diem, but most payers bill it as one unit per qualifying day. Nevada Medicaid, for example, allows one unit per day and five in seven rolling days. Check your contract.

Is H0035 outpatient or inpatient?

Outpatient. "Less than 24 hours" means the client goes home each day. It's billed on an outpatient facility claim or a professional claim with place of service 52 (53 for a CMHC).

What revenue code goes with H0035?

0912 or 0913, depending on the payer. Superior (Texas Medicaid) and TRICARE pair H0035 with 0912 (less intensive); other payers split the two by documented hours. Use your contract's pairing.

Does Medicare cover H0035?

No. Medicare pays PHP only to hospital outpatient departments and CMHCs, billing each service on its own line with a per diem by number of services, for clients certified as needing at least 20 hours a week.

Does Texas Medicaid (TMHP) pay H0035?

Through managed care plans that offer adult PHP as an in-lieu-of service, and through Texas Health Steps under 21. Superior lists H0035 with revenue code 0912 and requires the HCPCS code. Look up any fee-for-service fee in TMHP's Online Fee Lookup.

What is the difference between H0035 and S0201?

Both are PHP days under 24 hours. S0201 says per diem and isn't limited to mental health; H0035 names mental health and leaves the unit to the payer. Use the one your contract names.

What is the difference between H0035 and 90853?

H0035 is a whole PHP day; 90853 is one group psychotherapy session. Groups inside an H0035 day are already paid, so 90853 isn't billed on top.

Can H0035 be used for a substance use PHP?

Often, if the contract names it. Some payers want S0201 for substance use PHP. In Texas, a substance use PHP needs a chemical dependency treatment facility license.

Sources

• CMS, HCPCS quarterly update; HCPCS.codes, H0035, H0037 and G0410 (descriptors and coverage codes from the CMS file).
• CMS, place of service code set (POS 52 and 53).
• CMS, Medicare Benefit Policy Manual, chapter 6; Claims Processing Manual, chapter 4; eCFR, 42 CFR 410.43 and 42 CFR 424.24.
• Superior HealthPlan, PHP and IOP billing code update, September 2025; Texas HHSC, Uniform Managed Care Manual 16.3; TMHP, Online Fee Lookup.
• TRICARE For Life, PHP and IOP claims; CareSource, SUD fee schedule; Nevada Medicaid, web announcement 2001 (October 2019).
• 26 TAC §564.804 (Cornell LII).

CPT is a registered trademark of the American Medical Association; CPT descriptions here are paraphrased. General information, not billing or legal advice. Cima isn't a law firm or a billing company.