How Should Aquatic Therapy Be Documented for Reimbursement?

Nov 10
Learn how to document aquatic therapy sessions for CPT 97113 reimbursement — what payers expect, what auditors look for, and how to keep your notes audit-proof.

The Golden Rule: If You Didn’t Write It, It Didn’t Float

In the eyes of the law — and your payer — that aquatic therapy session only “happened” if you can prove it on paper (or EMR).

CPT 97113 is not a passive code. It represents skilled therapeutic exercise in a water environment — and that means your documentation has to clearly reflect why the session required water, what was done, and how the patient responded.
Fail that, and the claim sinks — no matter how clinically brilliant your session was.

What Medicare and Insurers Expect

The Centers for Medicare & Medicaid Services (CMS) Local Coverage Determination (LCD L34241) defines aquatic therapy as a therapeutic procedure involving exercises in water performed by a licensed provider to address functional deficits (CMS LCD L34241).

That LCD — and nearly every private insurer’s policy — shares the same essential documentation requirements:

1. Medical necessity: Prove why the patient needs aquatic therapy (e.g., pain or weakness prevents full weight-bearing on land).

2. Therapist skill: Show clinical reasoning, manual cues, and progression — not just observation.

3. Functional goals: Tie each aquatic activity to measurable change (ROM, balance, endurance, gait).

4. Specific water environment: Note pool depth, temperature, and resistance features used.

5. Timed service: Bill in 15-minute increments with matching documentation.
If that sounds like overkill, it’s because CMS assumes that aquatic therapy is a premium intervention — one that needs justification above and beyond “patient enjoyed pool.”

What Medicare and Insurers Expect

Every solid aquatic therapy note includes five anchor sections:

1. Subjective:

o Patient’s report of pain, confidence, or fatigue in water.
o Comparison to land sessions (e.g., “reports less pain with partial immersion”).

2. Objective:

o Clinical interpretation of patient’s performance.
o Documentation of how aquatic properties aided improvement.
Example: “Buoyancy allowed normal gait cycle without quadriceps insufficiency when a 50% reduction in weight-bearing was provided."

3. Assessment:

o Clinical interpretation of patient’s performance.
o Documentation of how aquatic properties aided improvement including:
  • Access - Immersion allows treatment of multiple areas quickly, improves therapist access to the patient’s body, and makes handling easier.
  • Aerobic Effects - Water-based aerobic exercise improves conditioning and overall health.
  • Balance & Safety - Patients can be challenged past their limits of stability without the fear of falling, improving balance reactions.
  • Cardiovascular Stress - Water exercise produces aerobic training effects with less cardiovascular stress compared to land.
  • Edema - Hydrostatic pressure reduces edema and effusion in the lower extremities.
  • Graded Resistance - Water provides 3-dimensional, velocity-dependent, graded resistance that is safer than land resistance.
  • Graded Weight-Bearing - Immersion decreases spinal and lower-extremity loading, enabling controlled progression of weight-bearing.
  • Movement Freedom - Water promotes freer movement, improving ROM, reducing stiffness, and increasing functional strength and mobility.
  • Muscular Effort - Standing in water reduces weight-bearing demands, lowering postural muscle requirements; limb elevation requires less effort than on land.
  • Pain - Buoyancy, temperature, and sensory changes contribute to pain reduction in the water.
  • Proprioception - Moving through water provides stronger somatosensory input than moving through air.
  • Thermal Effect - Water temperature can influence tone, arousal, muscle spasm, and pain.
  • Well-Being - Aquatic exercise promotes socialization and psychological well-being.

4. Plan:

o Record direct, one-on-one minutes.
o Each 15-minute unit equals one billable CPT 97113.

5. Timed Units:

o Record direct, one-on-one minutes.
o Each 15-minute unit equals one billable CPT 97113.

The American Physical Therapy Association (APTA) reminds clinicians:
“Documentation must demonstrate the complexity, skilled reasoning, and functional progress achieved — not just participation.”
(APTA.org)

What Not to Write

Auditors love vague notes because they make recoupment easy.
Phrases to banish from your aquatic therapy documentation:
• “Patient tolerated treatment well.”
• “Completed pool exercises.”
• “Good session.”
• “Walked laps.”

Instead, replace fluff with function:
• “Patient completed three sets of resisted hip abduction with water at ASIS level; required moderate verbal cueing for trunk alignment; improved stability noted.”

That’s what CMS and payers mean by skilled intervention.

Aquatic Environment Must Be Explicit

Water is your “treatment medium.”

Your note should name:
• Pool temperature if relevant: (e.g., 93 °F / 34 °C — ideal for pain and tone reduction).
• Depth: (e.g., “therapy performed at xiphoid depth for 50% weight reduction”).
• Equipment: (floats, gloves, resistance paddles).
• Location: (therapy pool vs. community pool).

Without that, your note reads like a land session that got wet — and auditors know the difference.

International Documentation Standards

• United Kingdom: The Chartered Society of Physiotherapy (CSP) requires that hydrotherapy notes identify pool temperature, depth, and safety observations, using the same SOAP format as land therapy (CSP.org.uk).

• Australia: Physiotherapists record specific aquatic modalities and outcomes tied to the Physiotherapy Practice Thresholds (2015).

• Canada: Documentation mirrors provincial physiotherapy standards; aquatic components must justify deviation from standard land care pathways.

Across countries, the same principle applies: water isn’t a luxury — it’s a clinical tool that must be documented with the same rigor as manual therapy or electrotherapy.

Sample Documentation Snippet (CPT 97113-Compliant)

“Aquatic therapy performed at chest-depth water (92 °F) using resistance gloves for upper-extremity strengthening. Completed 3×10 shoulder abductions with 3-second holds. Required moderate verbal cueing to maintain scapular control. Improved range by 15° compared to baseline. Continue aquatic sessions 2×/week; plan to transition to land-based pulley in 3 weeks.”
That paragraph tells an auditor everything they need to see: skilled reasoning, measurable change, a transition plan, and the reason water mattered.

Quick Audit-Proof Checklist

• Note includes medical necessity for water.
• Therapist provided skilled intervention (not observation).
• All exercises documented with reps and resistance.
• Pool environment described (temp, depth, tools).
• Functional outcome or measurable progress shown.
• Timed units align with billing.
• Signature and credentials included.

The Bottom Line

Aquatic therapy documentation isn’t busywork — it’s your legal armor.

Done right, it proves medical necessity, protects reimbursement, and communicates professional skill.

Done wrong, it invites denials, audits, and refund letters.

If you’re in the business of aquatic rehabilitation, your paper trail is part of the treatment.

Documentation Errors Summary

Frequent documentation errors resulting in claim denials for aquatic therapy services include:

Insufficient demonstration of medical necessity: Failure to clearly justify why aquatic therapy is indicated for the patient, especially compared to land-based therapy, is a common error. Documentation must specify patient-specific factors (e.g., comorbidities, physical limitations) that necessitate aquatic therapy.[1][3-4]

Lack of standardized outcome measures: Many studies and clinical notes lack validated, standardized tools to assess functional improvement, pain, or disability in the aquatic environment. This makes it difficult for payers to verify the effectiveness and necessity of the intervention.[1-2][4-5]

Incomplete reporting of treatment details: Omitting specifics such as the type of aquatic intervention, session duration, frequency, and progression of exercises can lead to denials. Documentation should include the exact nature of the therapy provided and the rationale for each component.[1][3-4]

Failure to document patient response and progress: Not recording objective changes in function, pain, or quality of life after aquatic therapy sessions is a frequent issue. Regular updates on patient progress using validated scales (e.g., Visual Analogue Scale, Functional Reach Test) are essential.[2-4]

Inadequate attention to patient safety and contraindications: Missing documentation regarding patient tolerance, adverse events, or contraindications (e.g., incontinence, feeding tubes) can result in denials, as payers require assurance of safe and appropriate care.[1][4]

Methodological flaws and poor quality evidence: Studies and clinical notes with high risk of bias, unclear reporting, or lack of intention-to-treat analysis are less likely to support claims. Ensuring robust, transparent documentation is critical for reimbursement.[1-4]

To minimize denials, documentation should be comprehensive, patient-specific, and utilize standardized outcome measures, with clear justification for aquatic therapy over alternative interventions.

1. VA Stroke Rehabilitation Guideline (2024)
Antonovich, N., Basch, J. K., Buelt, A., et al. (2024). Management of stroke rehabilitation (Practice guideline). U.S. Department of Veterans Affairs.

2. Aquatic PT for Chronic Low Back Pain (2022)
Ma, J., Zhang, T., He, Y., et al. (2022). Effect of aquatic physical therapy on chronic low back pain: A systematic review and meta-analysis. BMC Musculoskeletal Disorders, 23(1), 1050. https://doi.org/10.1186/s12891-022-05981-8

3. Aquatic Therapy in Stroke Rehab (2021)
Veldema, J., & Jansen, P. (2021). Aquatic therapy in stroke rehabilitation: Systematic review and meta-analysis. Acta Neurologica Scandinavica, 143(3), 221–241. https://doi.org/10.1111/ane.13371

4. Aquatic PT for Older Adults (2023)
Melo, R. S., Cardeira, C. S. F., Rezende, D. S. A., et al. (2023). Effectiveness of the aquatic physical therapy exercises to improve balance, gait, quality of life and reduce fall-related outcomes in healthy community-dwelling older adults: A systematic review and meta-analysis. PLOS ONE, 18(9), e0291193. https://doi.org/10.1371/journal.pone.0291193

5. Aquatic Assessment Tools (2020)
Cuesta-Vargas, A., Martin-Martin, J., Gonzalez-Sanchez, M., Merchan-Baeza, J. A., & Perez-Cruzado, D. (2020). Identification of tools for the functional and subjective assessment of patients in an aquatic environment: A systematic review. International Journal of Environmental Research and Public Health, 17(16), 5690. https://doi.org/10.3390/ijerph17165690