Hydrotherapy Equipment in Rehabilitation Clinics: What’s Used, What It Costs, and What the Evidence Supports

Key Takeaways

• The three main types of clinical hydrotherapy equipment — therapy pools, underwater treadmills, and resistance jet systems — serve different rehabilitation goals and patient populations.
• A purpose-built clinical hydrotherapy pool typically costs £200,000–£500,000+ to install (including the building works), with annual running costs of £30,000–£80,000 for heating, water treatment, and maintenance.
• Aquatic exercise programmes produce moderate improvements in pain and function for chronic musculoskeletal conditions — confirmed across 32 RCTs with 2,200 participants (Shi et al., 2023).
• Underwater treadmills are the most specialised (and expensive) pieces of equipment, used primarily for gait rehabilitation after stroke, spinal cord injury, and joint replacement.
• Many NHS trusts operate hydrotherapy facilities, but access varies significantly by region and waiting times can be long.

The Three Core Equipment Categories

Rehabilitation clinics use hydrotherapy equipment that falls into three main categories. Each serves a different clinical purpose, and the evidence base varies between them.

1. Hydrotherapy Pools (Therapeutic Pools)

What they are: Purpose-built pools maintained at 33–36 °C (warmer than standard swimming pools at 26–28 °C). They’re typically smaller than swimming pools — often 3 × 5 metres to 4 × 8 metres — with variable-depth floors, handrails, and hoist access for patients with limited mobility.

What they’re used for: General aquatic exercise, post-surgical rehabilitation, chronic pain management, neurological rehabilitation. The warm temperature and controlled environment allow physiotherapists to work with patients who cannot tolerate land-based exercise.

Evidence: This is the most studied category. The 2023 meta-analysis by Shi et al. (32 RCTs, 2,200 participants) found moderate improvements in pain, function, and quality of life for chronic musculoskeletal conditions including osteoarthritis, chronic low back pain, and fibromyalgia. The evidence specifically supports supervised aquatic exercise programmes — not just soaking.

Costs: Purpose-built clinical pools cost £200,000–£500,000+ including building works, water treatment systems, hoists, and accessibility features. Annual running costs (heating, water treatment, maintenance, staffing) typically run £30,000–£80,000 depending on size and usage. This is why many smaller NHS trusts don’t have their own facility — the capital investment is significant.

NHS availability: Many NHS trusts operate hydrotherapy pools, including the Royal Orthopaedic Hospital Birmingham, Frimley Health, University Hospitals Plymouth, Alder Hey Children’s Hospital, and the Robert Jones and Agnes Hunt Orthopaedic Hospital (RJAH). Access is via physiotherapy referral. Waiting times vary considerably by region.

2. Underwater Treadmills

What they are: Enclosed chambers containing a treadmill belt, adjustable water level, and often resistance jets. Patients walk or run with partial body-weight support from the water. The water level can be adjusted to control how much weight the patient bears.

What they’re used for: Gait rehabilitation (relearning to walk after stroke, spinal cord injury, or lower limb surgery), post-surgical knee and hip rehabilitation, and sports injury recovery. They’re also used in elite sport for maintaining cardiovascular fitness while injured.

Evidence:

• Jung et al. (2014) found improved walking ability and balance in spinal cord injury patients using underwater treadmill training
• Post-knee-replacement trials show improved range of motion and reduced swelling when underwater treadmill work supplements land-based rehabilitation
• Park et al. (2017) found benefits for gait parameters in stroke patients

Costs: Clinical underwater treadmill units (e.g., HydroWorx, SwimEx, Endless Pool) range from £30,000 to £120,000 depending on features. They require less space than a full pool but still need plumbing, drainage, and water treatment infrastructure. Installation costs add £10,000–£30,000.

Limitation: These are single-patient units. A physiotherapist and patient use the equipment one-on-one, which limits throughput compared with group sessions in a pool. This makes them expensive per-patient-hour.

3. Resistance Jet Systems and Whirlpools

What they are: Smaller units with adjustable water jets that provide resistance for exercise or massage for pain relief. In clinical settings, these are often built into therapy pools or available as standalone whirlpool baths.

What they’re used for: Upper and lower extremity rehabilitation (submerging a limb and exercising against jet resistance), post-exercise recovery, wound care (historically — this application has declined), and general pain management.

Evidence: Less studied as standalone equipment. The therapeutic benefit likely derives primarily from the warm water immersion rather than the jets specifically. A 2024 study found whirlpool therapy combined with exercise improved peripheral circulation in PAD patients (Mika et al., 2024), but isolating the jet contribution from the warm water contribution is difficult.

Costs: Clinical whirlpool baths (extremity-specific) range from £2,000–£15,000. Full-body clinical whirlpools cost £5,000–£25,000. These are more accessible for smaller clinics than full pool installations.

What the Research Says About Clinical Outcomes

Across the evidence base, the outcomes from clinical hydrotherapy are consistently positive but moderate. Here is an honest summary:

Outcome	Evidence	Magnitude
Pain reduction (chronic musculoskeletal)	32 RCTs, 2,200 patients	Moderate improvement vs. control
Physical function improvement	Multiple meta-analyses	Moderate improvement
Quality of life	32 RCTs	Small to moderate improvement
Post-surgical function	8 controlled trials, 287 patients	Improved daily activities vs. land only
Post-surgical wound complications	8 controlled trials	No increase (safe when wound closed)
Fibromyalgia symptoms	Multiple systematic reviews	Improved pain, function, quality of life

The consistent finding: hydrotherapy is as effective as land-based therapy for most outcomes, and sometimes better — not because the water produces dramatically different results, but because it allows patients to exercise who otherwise couldn’t tolerate it. This is particularly valuable for patients with severe joint pain, post-surgical patients in early recovery, and older adults with balance problems.

Practical Considerations for Clinics

Space and Infrastructure

A hydrotherapy pool requires significant infrastructure beyond the pool itself: water treatment and filtration, temperature control, changing facilities with accessible showers, hoist systems for patients with limited mobility, and non-slip flooring. The building must manage high humidity to prevent structural damage. Many clinics that want to offer hydrotherapy but lack pool infrastructure partner with local facilities (public pools with warm water sessions, or hotel/leisure centre pools with suitable temperatures).

Staff Training

Physiotherapists using hydrotherapy equipment need specific aquatic therapy training. In the UK, the Aquatic Therapy Association of Chartered Physiotherapists (ATACP) provides courses and maintains standards. Key competencies include pool safety, aquatic exercise prescription, and understanding how water properties alter biomechanics. A poolside physiotherapist also needs to manage the additional risk of working with vulnerable patients near water.

Infection Control

Clinical pools serve patients with surgical wounds, compromised immune systems, and skin conditions. Water quality monitoring must be more rigorous than standard swimming pools. This includes regular testing for Pseudomonas aeruginosa and Legionella, alongside standard chlorine and pH monitoring. Many NHS trusts follow Public Health England (now UKHSA) guidance on managing hydrotherapy pool water quality.

The Business Case: Is Hydrotherapy Equipment Worth the Investment?

This is a question clinic managers regularly face. The honest answer: it depends on patient volume and case mix.

Arguments for investment:

• Patients who cannot tolerate land-based exercise (severe OA, early post-surgical, neurological conditions) have no equivalent alternative
• Group sessions in a pool (4–8 patients per physiotherapist) can be more efficient than one-to-one land-based sessions
• Patient satisfaction with hydrotherapy is consistently high, which supports retention and referral rates
• The evidence base is strong enough to justify use to commissioners and funders

Arguments against:

• High capital cost (£200,000–£500,000+ for a pool) with long payback periods
• Annual running costs are substantial, particularly energy for heating
• Long-term outcomes may not differ significantly from well-delivered land-based physiotherapy
• Pool downtime for maintenance affects scheduling

Many private rehabilitation clinics find that an underwater treadmill (£30,000–£120,000) offers a middle ground — providing the water-based rehabilitation option without the full infrastructure cost of a pool.

The Bottom Line

Hydrotherapy equipment in rehabilitation clinics serves a genuine clinical need. The evidence shows it improves outcomes for patients who cannot exercise on land, and it’s safe even in early post-surgical rehabilitation. The three main equipment types — pools, underwater treadmills, and resistance jets — each serve different clinical niches.

However, the equipment is expensive, and the outcomes are moderate rather than dramatic. The water and the exercise programme it enables — not the technology — are the therapeutic agents. A well-run aquatic exercise class in a warm public pool may produce outcomes comparable to a session using a £100,000 underwater treadmill, for many patient populations.

For clinics considering the investment, the question is whether the patient volume and case complexity justify the capital cost. For patients seeking hydrotherapy, the question is simpler: ask your physiotherapist for access to warm water exercise. The specific equipment matters less than getting into the water and moving.

References

• Shi, Z. et al. (2023). Efficacy of aquatic exercise in chronic musculoskeletal disorders: a systematic review and meta-analysis of 32 RCTs. Journal of Orthopaedic Surgery and Research, 18, 895. PMC10704680
• Villalta, E.M. & Peiris, C.L. (2013). Early aquatic physical therapy improves function and does not increase risk of wound-related adverse events. Archives of Physical Medicine and Rehabilitation, 94(1), 138–148. ScienceDirect
• Rahmann, A.E. et al. (2009). A specific inpatient aquatic physiotherapy program improves strength after total hip or knee replacement surgery. Archives of Physical Medicine and Rehabilitation, 90(5), 745–755. PubMed
• Mika, P. et al. (2024). Evaluation of peripheral circulatory changes following hydrotherapy and controlled physical training. Life, 14(12), 1578. MDPI
• McVeigh, J.G. et al. (2008). The effectiveness of hydrotherapy in the management of fibromyalgia syndrome: a systematic review. Rheumatology International, 29, 119–130. PubMed
• Jung, T. et al. (2014). Effects of aquatic treadmill training on gait in spinal cord injury: a randomised controlled trial. Spinal Cord, 52, 822–829.
• Park, J. et al. (2017). Effects of underwater treadmill gait training on gait parameters in stroke patients. Journal of Physical Therapy Science, 29(12), 2203–2206.