Pool Therapy, Aquatic Therapy or Hydrotherapy — CPB 0174 | AETNA Coverage Update

Aetna modified CPB 0174 for aquatic therapy (pool therapy, hydrotherapy), effective September 26, 2025. Here's what changes for billing teams.

Aetna, a CVS Health company, updated its aquatic therapy coverage policy under CPB 0174 in the Aetna aquatic therapy coverage policy governing CPT 97113 and CPT 97036. The core rules stay intact, but this modification clarifies exactly where medical necessity ends and where maintenance therapy begins — a distinction that will drive more claim denials if your documentation doesn't hold up.

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Quick-Reference Table

Field	Detail Copy
Payer	Aetna, a CVS Health company
Policy	Pool Therapy, Aquatic Therapy or Hydrotherapy
Policy Code	CPB 0174 Aetna
Change Type	Modified
Effective Date	September 26, 2025
Impact Level	High
Specialties Affected	Physical therapy, occupational therapy, rehabilitation medicine, neurology, orthopedics, oncology
Key Action	Audit active aquatic therapy authorizations before September 26, 2025 — any maintenance-only cases will not meet medical necessity under this policy

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Aetna Aquatic Therapy Coverage Criteria and Medical Necessity Requirements 2025

The Aetna aquatic therapy coverage policy under CPB 0174 draws a hard line. Aquatic therapy is medically necessary when it treats a musculoskeletal condition and the member is making measurable functional progress.

The moment progress stops — when your patient is maintaining but not improving — Aetna calls it maintenance therapy. Maintenance therapy is not medically necessary under this policy. That's not a gray area. It's a flat exclusion.

For CPT 97113 (aquatic therapy with therapeutic exercise) and CPT 97036 (Hubbard tank, each 15 minutes), your documentation has to show active functional improvement. Subjective notes like "patient tolerating therapy well" or "continues to benefit from pool exercise" are not enough. You need objective, measurable progress documented at each visit.

This is the same framework Aetna applies to land-based therapeutic exercise. The water doesn't change the rules — it just changes the treatment setting. Your billing guidelines for aquatic therapy need to match the same documentation standards you use for CPT 97110 and similar codes.

Prior authorization requirements vary by plan. Check the member's specific Aetna plan before scheduling — some Aetna commercial plans require prior auth for physical therapy services, including aquatic therapy. Don't assume a standard commercial plan mirrors the coverage policy language. The coverage policy sets the medical necessity floor; the member's benefit design sets the access rules on top of that.

Reimbursement for CPT 97113 is billed per 15-minute unit. Document your time precisely. Aetna auditors will look at whether the number of billed units matches the clinical record.

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Aetna Aquatic Therapy Exclusions and Non-Covered Indications

Maintenance therapy is the primary exclusion here. Aetna defines maintenance therapy as treatment carried out only to maintain the member's current level of function — meaning neither improving nor regressing.

This matters most in two scenarios your billing team sees regularly.

First, chronic condition management. Patients with Parkinson's disease (G20.A1–G20.C), Alzheimer's disease (G30.0–G30.9), or other progressive neurological conditions often plateau. Once they plateau, continued aquatic therapy is maintenance — and Aetna will deny it.

Second, post-surgical rehab late in the episode of care. A patient six months out from a total knee replacement may still feel better in the pool, but if range of motion and functional scores have stabilized, you're billing maintenance therapy. That's a claim denial waiting to happen.

The real issue here is that maintenance therapy denials are often retroactive. Aetna reviews the full episode, not just the most recent dates of service. If your documentation shows plateau at visit 12 but you billed through visit 24, expect a demand for repayment on visits 12 through 24.

Document functional status at every visit. Use objective measures — FIM scores, Timed Up and Go, grip strength, range of motion in degrees — not narrative descriptions.

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Coverage Indications at a Glance

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Aetna Aquatic Therapy Billing Guidelines and Action Items 2025

Copy Action Items

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CPT, HCPCS, and ICD-10 Codes for Aquatic Therapy Under CPB 0174

Covered CPT Codes (When Selection Criteria Are Met)

Code	Type	Description Copy
97113	CPT	Therapeutic procedure, one or more areas, each 15 minutes; aquatic therapy with therapeutic exercise
97036	CPT	Application of a modality to one or more areas; Hubbard tank, each 15 minutes

Other CPT Codes Related to CPB 0174

These codes are referenced in the policy but are not listed as covered under CPT 97113/97036 criteria. Coverage for these depends on the individual plan and indication.

Code	Type	Description Copy
97022	CPT	Application of a modality to 1 or more areas; whirlpool
97124	CPT	Therapeutic procedure, 1 or more areas, each 15 minutes; massage, including effleurage, petrissage

Key ICD-10-CM Diagnosis Codes

CPB 0174 references 123 ICD-10-CM codes. The full list is below. Every diagnosis listed still requires documented functional improvement to satisfy medical necessity.

The policy references 43 additional ICD-10-CM codes not fully listed in the extracted data above. Access the full code list at the CPB 0174 Aetna policy source.

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