CurrentAetnaPolicy 0174

Pool Therapy, Aquatic Therapy or Hydrotherapy

Governs Aetna's coverage stance for pool therapy/aquatic therapy/hydrotherapy for members, defining medical necessity, investigational indications, billing limits, and applicable codes for musculoskeletal and other conditions.

Policy Summary

PayerAetna

PolicyPool Therapy, Aquatic Therapy or Hydrotherapy

Policy CodePolicy 0174

Change TypeNo material change

Effective Date09/22/1997

Next Review Date02/08/2024

Key ActionDocument objective functional loss in the medical record and ensure one-to-one provider patient contact to support medical necessity for aquatic therapy.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

musculoskeletalCoverage stance

maintenanceNot medically necessary

3-4x/wkTypical frequency

1:1Provider contact

97036, 97113Example codes

04/07/2023

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Coverage Criteria for Aquatic / Pool / Hydrotherapy

Medical Necessity Criteria for Aquatic Therapy

Covered when ALL of the following are met

Medical Necessity for Musculoskeletal Conditions: Aquatic therapy (hydrotherapy, pool therapy) is considered medically necessary for musculoskeletal conditions.

Policy medical necessity statement; applies to musculoskeletal indications.

Restorative Purpose (Not Maintenance): Aquatic therapy must be carried out to restore the member's level of function lost or reduced by injury or illness; aquatic therapy provided solely to maintain function (no improvement or decline) is not medically necessary.

Maintenance therapy is considered not medically necessary.

Objective Documentation: Medical record must document objective loss of joint motion, strength, mobility, or function (e.g., degrees of motion, strength grades, levels of assistance) to support medical necessity.

Supports determination of medical necessity.

Provider Contact and Billing: Provider must have direct one-to-one patient contact when reporting aquatic therapy; supervising multiple patients in a pool and billing each per 15-minute interval is inappropriate. Only professional charges for licensed providers delivering direct one-to-one care are covered; charges for pool use or group aquatic exercise programs are not covered.

Ensures appropriate professional billing and avoids inappropriate group billing.

Treatment Parameters: Aquatic therapy should be delivered with standard treatment frequency/duration (typically 3–4 sessions per week for 2–4 weeks) and be described in the record (modality, water depth/temperature when relevant, session duration and frequency).3-4x/week for 2-4 weeks

Documentation of session parameters and planned course supports medical necessity and prior authorization when required.

Evidence summaries and applicability

Summary of clinical evidence and applicability considerations

Improving Balance and Fall‑Risk Factors in Older Adults: Systematic reviews report aquatic exercise can improve modifiable physical fitness components linked to fall risk and dynamic balance (meta-analysis SMD approx -1.13), but the overall evidence is limited by low quality, heterogeneity (high I2), and poorly described interventions.limited, low-to-moderate quality evidence

Further high-quality, adequately powered, and well-described trials are needed to define replicable aquatic training protocols for fall-risk reduction.

Peripheral Artery Disease (PAD): A single randomized trial (12-week aquatic walking, n=72) showed reduced leg arterial stiffness and resting heart rate and improvements in V̇o2max, 6‑minute walk distance, physical function, and muscle strength with high adherence (84%).preliminary single RCT

Findings are promising but require validation in additional well-designed studies.

Aquatic therapy and related modalities are considered experimental and investigational for non-musculoskeletal indications because effectiveness has not been established. Examples listed in the policy include treatment of asthma, atopic dermatitis, autism, chronic obstructive pulmonary disease (COPD), developmental coordination disorder, end-stage dementia, risk-of-falls reduction in the elderly, lymphedema, management of individuals with cancer, neonatal brachial plexus palsy, peripheral artery disease, psoriasis, sickle cell anemia, stroke rehabilitation, and traumatic brain injury. Specific modalities also designated investigational include passive hydrotherapy WATSU (WaterShiatsu), crenobalneotherapy (spa therapy), and nano-bubble hydrotherapy for listed indications.

Only the professional charges of a licensed provider delivering direct one-to-one aquatic therapy are covered. The policy explicitly excludes coverage for charges for aquatic exercise programs or separate charges for use of a pool. Supervising multiple patients in the pool and billing each patient for the same 15‑minute interval is inappropriate and may be subject to denial.

The Cochrane review of water-based exercise in COPD specifically excluded swimming from eligible interventions; the review focused on supervised water-based exercise programs rather than swimming per se.

Several evidence reviews and background sections note limitations in applicability: many studies excluded pediatric populations (for example, neonatal brachial plexus palsy literature lacks trials on early hydrotherapy), and emerging or novel techniques such as nano-bubble hydrotherapy remain developmental and are not described in standard clinical references. These factors limit generalizability and support the investigational classification for some techniques and populations.

The Clinical Policy Bulletin provides a partial, general description of Aetna plan benefits and administrative guidance; it does not constitute a contract or a guarantee of coverage. Specific plan provisions, documentation requirements, or exclusions may vary by member plan and should be verified against applicable benefit documents.

Aquatic therapy provided solely as maintenance therapy—that is, to preserve a current level of function without demonstrable improvement or decline—is considered not medically necessary and may be denied.

For upper‑limb lymphedema, systematic review evidence from randomized trials indicates no significant short‑term difference between aqua lymphatic therapy and standard land‑based care for lymphedema status or upper‑limb physical function, supporting non‑superiority of aquatic lymphatic approaches in current evidence.

The evidence base for WATSU (WaterShiatsu) is limited: systematic reviews and meta‑analyses found effect sizes suggesting benefit for pain, physical function and mental health, but the overall grade of evidence was estimated to be low‑to‑moderate. Few high‑quality randomized controlled trials exist and reporting/methodological shortcomings (e.g., limited control groups, poor reporting) limit confidence in definitive conclusions.

Billing and Code Guidance

Covered CPT CodesCPTCovered

97036	Application of a modality to one or more areas; Hubbard tank, each 15 minutes.
97113	Therapeutic procedure, one or more areas, each 15 minutes; aquatic therapy with therapeutic exercises.

ICD-10 Codes Covered (when selection criteria are met)ICD-10Covered

M30.3	Diseases of the musculoskeletal system and connective tissue (range M30.3 - M99.9 represented in policy).
S00.00	Injury (range S00.00 - S99.929 represented in policy).
Z87.81	Personal history of injury (range Z87.81 - Z87.828 represented in policy).
Z51.89	Encounter for other specified aftercare [physical therapy].

ICD-10 Codes Not Covered / Investigational Indications (examples)ICD-10Not Covered

C00.0	Neoplasms (range C00.0 - D49.9 represented in policy).
D57.0	Sickle cell disorders (range D57.0 - D57.819).
G30.0	Alzheimer's disease (range G30.0 - G30.9).
I61.0	Nontraumatic intracerebral hemorrhage (range I61.0 - I61.9).
M17.0	Osteoarthritis of knee (codes M17.0 - M17.9 listed as not covered for certain modalities).
M54.50	Low back pain (codes M54.50 - M54.9 listed as not covered for certain modalities).

Modalities Considered Experimental/InvestigationalmixedExperimental

No specific CPT code	Passive hydrotherapy WATSU - no specific CPT code; considered not covered for listed indications.
No specific CPT code	Crenobalneotherapy - no specific CPT code; considered not covered for listed indications.
No specific CPT code	Nano-bubble hydrotherapy - no specific CPT code; considered not covered for listed indications.

Referencesmixed

See References 1-25

Full reference list in policy References section (includes Cochrane reviews, randomized trials, and guidelines).

Coding References / Placeholdersmixed

ICD-10 ranges	Policy lists multiple ICD-10 ranges; see policy text for full enumerations (e.g., M30.3-M99.9, S00.00-S99.929).
No specific CPT code	Several experimental modalities have no specific CPT code and are noted as not covered for listed indications.

Standard treatment frequency/duration

Standard treatment frequency/durationStandard treatment duration is 3 to 4 times per week for 2 to 4 weeks.

Provider Billing, Authorization and Documentation Actions

Prior Authorization

Prior Authorization/Selection Criteria for Covered Codes

Prior authorization/selection criteria: Coverage of listed CPT codes (e.g., 97036, 97113) is contingent on meeting the medical necessity selection criteria in this bulletin and documentation in the medical record demonstrating objective loss of joint motion, strength, mobility or function related to a specific disease or injury. Aquatic therapy is considered medically necessary only for musculoskeletal conditions and not for maintenance therapy (no improvement/regression).

Covered CPT codes (when selection criteria met): 97036, 97113
ICD-10 covered ranges: M30.3–M99.9; S00.00–S99.929; Z87.81–Z87.828; Z51.89

Prior Authorization

Prior authorization for aquatic interventions

Prior authorization for aquatic interventions: Prior authorization may be advised or required by some plans for aquatic interventions, particularly for special populations or conditions discussed in the evidence (for example PAD, severe TBI) or when utilization exceeds plan or physical therapy benefit limits. Verify and obtain any required prior authorization before initiating therapy when plan rules indicate.

Background and Rationale

Aquatic therapy uses water properties such as buoyancy and resistance to relieve symptoms and restore function when joint motion, strength, mobility or overall function are reduced by injury or illness. Standard treatment patterns cited in the policy are typically 3–4 sessions per week for 2–4 weeks, and interventions include supervised water‑based exercise, aquatic walking, passive techniques (e.g., WATSU), and other hydrotherapy variants.

Definitions and Modality Descriptions

Definition — Aquatic therapy / hydrotherapy / pool therapy (therapeutic use of water properties)

TermAquatic therapy / hydrotherapy / pool therapy

DefinitionTherapeutic use of water's properties (e.g., buoyancy, resistance) to restore lost or reduced function due to injury or illness; considered a physical therapy modality.

Coverage contextConsidered medically necessary for musculoskeletal conditions when used to restore function (not for maintenance).

Definition — Aquatic therapy / water-based exercise (supervised pool exercise; methods include Halliwick, Bad Ragaz, etc.)

TermAquatic therapy / water-based exercise

DefinitionSupervised exercise performed in a pool using principles such as buoyancy and resistance; methods referenced include Halliwick, Ai Chi, Bad Ragaz, aquatic treadmill/walking, and aqua lymphatic therapy.

Policy Summary

PayerAetna

PolicyPool Therapy, Aquatic Therapy or Hydrotherapy

Policy CodePolicy 0174

Change TypeNo material change

Effective Date09/22/1997

Next Review Date02/08/2024

Key ActionDocument objective functional loss in the medical record and ensure one-to-one provider patient contact to support medical necessity for aquatic therapy.

SourceLink

On This Page

Severe Traumatic Brain Injury (sTBI):

A small RCT (n=20) comparing aquatic therapy to conventional land-based rehabilitation found within-group improvements in balance, gait, ADL, and quality of life over 4 weeks; results are preliminary and need confirmation in larger studies.

Preliminary evidence only; further trials needed.

WATSU (Passive Hydrotherapy) in Juvenile Idiopathic Arthritis and Other Indications: One randomized trial (JIA, n=46) and systematic reviews/meta-analyses suggest WATSU may improve HR‑QoL, pain, and function, with meta-analytic effect sizes favoring benefit; overall evidence quality is low-to-moderate and methodological limitations limit external validity.low-to-moderate evidence

High-quality RCTs with improved methodology are recommended to strengthen conclusions about WATSU.

Crenobalneotherapy and Spa‑Type Treatments: Systematic reviews show inconsistent but sometimes favorable effects of crenobalneotherapy (spa/mineral water approaches) for limb osteoarthritis and low back pain; methodological shortcomings and small sample sizes limit definitive conclusions, though some trials of good quality indicate potential usefulness.inconclusive overall

Better-designed trials are needed to determine the role and mechanisms of mineral‑water based therapies.

Oncology, Dermatology, and Other Non‑Musculoskeletal Uses: Systematic reviews in cancer, atopic dermatitis, and psoriasis report heterogeneous results with variable study quality; some studies report symptom or QOL improvements, but heterogeneity and methodological limitations preclude clear statements of effectiveness.heterogeneous evidence

Current evidence does not establish effectiveness for many non‑musculoskeletal indications; these uses are considered investigational in the policy.

Emerging Technologies (Nanobubble, US‑assisted Bubble Therapies): Nanobubble and ultrasound‑assisted bubble therapies are described as emerging biomedical technologies with potential applications (e.g., drug delivery), but clinical applications remain developmental and investigational.investigational

Clinical validation and reproducible generation methods are lacking; these modalities are considered investigational.

Consider prior authorization for complex cases (e.g., peripheral artery disease, severe traumatic brain injury)

Aquatic therapy is subject to physical therapy benefit limits (see CPB 0325)

Prior Authorization

Prior authorization — verify per plan

Verify per plan: Always verify member-specific benefits, prior authorization requirements, and plan procedures (including Clinical Policy Bulletin cross-references) before scheduling services. The Clinical Policy Bulletin is not a contract — follow the member's plan for authorization rules and benefit limitations.

Follow plan-specific prior authorization and benefit verification processes
Reference CPB 0325 for physical therapy benefit limits

Note

Background does not specify authorization or billing rules

No explicit authorization or billing requirements stated: The clinical background and evidence sections do not by themselves establish explicit prior authorization or billing rules. Provider must follow the member's plan and Clinical Policy Bulletin procedures to determine authorization and billing requirements.

Background evidence summaries do not substitute for plan-level authorization rules
Provider responsibility to check plan/Clinical Policy Bulletin notes

Denial Risk

Insufficiently described interventions risk non-coverage

Risk of non-coverage for insufficiently described interventions: Interventions that are poorly or insufficiently described in the medical record (lack of modality, session parameters, objective findings, or treatment rationale) increase the risk of denial. Provide clear documentation of the aquatic modality used, session duration/frequency, and clinical response.

Describe exercises performed, water depth/temperature when relevant, use of equipment, and session parameters (minutes, frequency)
Avoid vague descriptions; ensure reproducible session detail to support medical necessity

Documentation Required

Objective Functional Loss Documentation

Objective functional loss documentation: The medical record should document objective measures of loss or restriction (e.g., degrees of joint motion, strength grades, levels of assistance, 6-minute walk distance) that justify aquatic therapy and show progress over time. Standard treatment frequency noted in literature is typically 3–4 times/week for 2–4 weeks; document goals and expected measurable improvement.

Document baseline objective findings (ROM degrees, strength grade, gait/mobility measures)
Record measurable goals, session frequency, and evidence of improvement or progression
Standard treatment duration referenced: 3–4× per week for 2–4 weeks

Documentation Required

No explicit documentation requirements listed — provider responsibilities

No explicit documentation requirements section: While this bulletin outlines needed clinical elements (objective loss, modality, session parameters, response), it does not list a regulatory checklist. Providers must include diagnosis, aquatic modality, session parameters (duration/frequency), supervising licensed provider identity, and objective response in the medical record to support coverage.

Required clinical elements to document: diagnosis, aquatic modality, session minutes and frequency, licensed provider one-to-one contact, objective outcome measures
Note that only professional charges for licensed providers with direct one-to-one contact are covered; group supervision billing is inappropriate

Note

Adjunct or Sequential Therapy Consideration

Adjunct or sequential therapy consideration: Aquatic therapy may be used alone or as an adjunct to land-based exercise. Document the clinical rationale when aquatic therapy is used to enable performance of exercises that cannot be done on land or to facilitate progression to land-based therapy.

State whether aquatic therapy is being used because the member cannot perform land-based exercises effectively or to transition to land-based therapy
Do not bill multiple hydrotherapy modalities for the same visit

Clinical uses notedUsed for musculoskeletal rehabilitation and studied in stroke, COPD, PAD and other populations; protocols vary across trials.

Definition — Endurance shuttle walk distance (ESWD) — outcome measure referenced in COPD trials

TermEndurance shuttle walk distance (ESWD)

DefinitionAn outcome measure of endurance exercise capacity used in COPD trials; reported as improved with water-based exercise in included studies (example: MD 371 meters; 95% CI: 121 to 621 meters in one study).

ContextIncluded in Cochrane review of water-based exercise for COPD comparing supervised water-based versus land/no exercise training.

Definition — WATSU (WaterShiatsu) passive hydrotherapy technique description

TermWATSU (WaterShiatsu)

DefinitionA passive hydrotherapy technique performed in chest‑deep thermoneutral water (~35°C) combining myofascial stretching, joint mobilization, massage and shiatsu; typically delivered in sessions (example: 10 sessions of 45 minutes once-weekly in a JIA trial).

Evidence summarySmall RCTs and systematic reviews report improvements in HR‑QOL, pain and function but overall evidence quality is low-to-moderate and further high-quality RCTs are needed.

Definition — Nanobubble hydrotherapy (novel technique description)

TermNanobubble hydrotherapy

DefinitionHydrotherapy variant involving infusion of compressed air into water to form clouds of tiny (nano) bubbles; proposed mechanisms include effects on skin cells and vasculature and potential biomedical applications under development.

Development statusDescribed as an emerging/experimental technology with ongoing research; clinical applications remain investigational.

References — numbered literature citations for aquatic therapy modalities

Key citationsSelected references include Epps et al. (hydrotherapy RCT in JIA), Forestier et al. (crenobalneotherapy reviews), and Iliescu et al. (2020) systematic review on aquatic therapy in stroke).

Reference rangeFull reference list numbered in the policy; references cited span items 10–36 and 54–62 (policy contains ~79 numbered citations).

Most relevant reviews/trialsCochrane review of water-based exercise in COPD (McNamara et al., included in background) and Iliescu et al. (2020) stroke meta-analysis are among key evidence sources.