Hot tubs and spa pools are attractive features in hotels, lodges, holiday parks and serviced accommodation. They enhance guest experience and drive bookings.
They are also recognised sources of Legionnaires’ disease outbreaks when not properly managed.
Warm, aerated water, high bather loads and complex pipework create conditions that can allow bacteria to multiply rapidly. UK guidance treats spa pools as higher-risk systems for this reason.
For hospitality operators, this means hot tubs require structured oversight – not informal maintenance.
Why Hot Tubs Present a Higher Risk
Spa pools typically operate between 30-40 °C, well within the temperature range where Legionella bacteria can grow.
Unlike swimming pools, they:
Cosmetics, perspiration, skin cells and other contaminants increase the nutrient load in the water. When disinfectant levels fluctuate, which they can do quickly in busy settings, microbiological growth can occur within hours.
In addition to Legionella, guidance highlights risks from:
This combination of warmth, agitation and organic loading is what makes spa pools uniquely sensitive from a compliance perspective.
Legal Duties for Hospitality Operators
Under UK health and safety legislation, duty holders must:
This applies to:
Where five or more employees are present, significant findings must be recorded. Monitoring and inspection records are generally expected to be retained for at least five years.
Hot tubs cannot be managed casually. They must be managed deliberately.
We provide Legionella risk assessments and compliance reviews for hotels, holiday parks and serviced accommodation across the UK, ensuring your documentation aligns with both legal requirements and day-to-day operation.
Contact our team to discuss your hospitality water hygiene requirements.
Domestic-Type vs. Commercial-Type Spa Pools
One area that often confuses is the difference between domestic-type and commercial-type systems.
Domestic-Type Hot Tubs Used Commercially
Common in:
These are designed for small, discrete groups. Water should be replaced:
They are not suitable for high bather turnover or shared access across multiple accommodation units.
Commercial-Type Spa Pools
Common in:
These typically include:
The balance tank collects displaced and recirculated water and is an active part of the system. Because it stores warm water and organic material, it can become a source of contamination if not properly maintained.
UK guidance expects balance tanks to be:
Turnover time (how quickly the entire water volume passes through filtration and treatment) is typically:
The level of monitoring and control must reflect the type of system in use.
Bather Load and Water Replacement
One of the most common causes of hot tub failure is simple: too many users, not enough water replacement.
Guidance sets a clear expectation for design bather load:
For example, a 5m3 spa pool may be designed for up to 50 bathers per hour – but only if treatment systems are functioning correctly.
Exceeding this places immediate strain on:
Water replacement is equally critical.
In commercial settings, full water replacement should occur when:
For domestic-type systems used commercially:
When replacement intervals are extended, total dissolved solids rise, disinfectant effectiveness reduces, and bacterial growth becomes more likely.
Monitoring and Testing Requirements
Routine monitoring is not optional. It is the mechanism that proves control measures are working.
Chemical Parameters
Key operational ranges include:
If disinfectant levels fall significantly outside recommended ranges, the spa pool may require temporary closure until corrected.
High combined chlorine, elevated total dissolved solids, or persistent imbalance are warning signs that water replacement or system review is required.
Balance Tank Monitoring
Where fitted, balance tanks should be included in inspection routines. Guidance recommends:
Visible debris, biofilm or sediment within a balance tank is a warning sign that control measures require review.
Microbiological Testing
Minimum sample frequency:
Immediate closure is expected where there is:
These thresholds exist to protect users. When exceeded, corrective action must be swift and documented.
Written Scheme of Control
A compliant spa pool regime should include:
Records should capture:
In the event of inspection, documentation demonstrates due diligence.
Protecting Guests and Business Continuity
Spa pool failures are rarely caused by a single catastrophic event. They are usually the result of small control lapses – missed checks, delayed water replacement, unrecognised dosing faults.
Guidance recognises that outbreaks have occurred in hotels, holiday homes and leisure settings. When controls are not robust, the consequences can include enforcement action, reputational damage and temporary closure of facilities.
Effective spa pool management is therefore not simply about passing inspection. It is about protecting guests, safeguarding staff and maintaining business continuity.
If your hospitality setting operates a hot tub or spa pool, ensure that:
Where uncertainty exists, it is better to review the control regime proactively than to respond reactively after a failed result.
Hot tub systems require structured oversight and documented control. If you are unsure whether your monitoring regime, sampling frequency or written scheme aligns with current UK guidance, a proactive review can prevent costly disruption.
Contact our team to discuss your hospitality water hygiene requirements.