Soaking in a hot tub is a relaxing way to spend leisure time, especially with friends and family. It’s no wonder so many of the UK’s leading hotels offer swimming pools, spa areas, and hot tubs for guests. However, maintaining these facilities requires strict adherence to water hygiene management protocols to ensure they are safe and enjoyable for everyone.

Since many people often use these facilities at the same time, it’s essential to control the quality of the water to prevent illnesses and other health risks. This article covers the importance of water safety, and how frequently you should be changing pool or spa water in hotels and leisure centres.

Hygiene protocols and health regulations

Water hygiene is a top priority for anyone managing a public swimming pool, spa, or hot tub. The Health and Safety Executive (HSE) outlines regulations under the Health and Safety at Work Act 1974, Management of Health and Safety at Work Regulations 1999, and the Control of Substances Hazardous to Health Regulations 2002 (COSHH).  These regulations cover various aspects, including controlling legionella bacteria, which can develop into Legionnaires’ disease when inhaled via aerosol droplets produced by jets in hot tubs​.

Why are hot tubs particularly vulnerable to legionella bacteria?

Hot tubs are particularly susceptible to legionella due to their water temperature. The optimal temperature for human comfort (30°C) is also conducive to bacterial growth (20°C-45°C). Factors like sweat, lotions, and dirt add contaminants to the water, further encouraging bacterial development. If proper treatment with disinfectants (like chlorine or bromine) and water filtration is neglected, bacteria can thrive.

Moreover, water jets in hot tubs produce aerosols, tiny droplets of water that can be easily inhaled. If legionella bacteria are present in these droplets, they can cause respiratory infections similar to pneumonia​. If contaminated aerosols are inhaled by people using the hot tub or standing close by, the bacteria may travel directly into the lungs and develop into Legionnaires’ disease, a chest infection with pneumonia-like symptoms and breathing difficulties.

Instances of people catching Legionnaires’ disease after using hot tubs are thankfully few and far between. The worst outbreak occurred in 1999 at a Dutch flower show which originated from two infected whirlpool spas. In total, 188 visitors and exhibitors became ill, of which 163 were hospitalised with suspected Legionnaires’ disease – with 17 confirmed cases, including four fatalities.

Swimming pools in hotels: how often should you change the water?

In addition to hot tubs and spa pools, swimming pools in hotels are a significant attraction for guests. To maintain safe, hygienic conditions, it’s essential to follow strict water management protocols. Unlike spa pools, swimming pool water typically doesn’t require frequent changes if the right filtration systems and chemical treatments are consistently applied.

For most hotel swimming pools, water doesn’t need to be entirely replaced frequently. Instead, a continuous filtration system paired with regular backwashing (to clean the filters) can keep the water clear and sanitary. According to the Pool Water Treatment Advisory Group (PWTAG), hotels should replace about 30 litres of water per guest per day in the pool. Full water changes may only be necessary once or twice a year, depending on usage, and when proper chemical treatments and filtration are in place​.

Essential water safety for hotel swimming pools

Maintaining water safety in hotel swimming pools is essential to prevent the spread of waterborne diseases and contaminants. Key safety measures include daily testing of chlorine and pH levels to ensure they stay within recommended ranges. Chlorine should generally be kept between 1-3 mg/l, while pH should be maintained between 7.0-7.6. Failure to do so can result in the growth of harmful bacteria such as E. coli and Pseudomonas, which can lead to rashes, respiratory infections, or more serious health issues​.

In addition to chemical balance, proper pool circulation is essential to prevent stagnation, which can lead to the development of harmful microorganisms. Pool operators should  regularly clean pool walls, floors, and filtration systems to prevent dirt and biofilm accumulation, which may compromise water quality.

Equally important is poolside safety, which involves ensuring anti-slip flooring is in place and having clear signage regarding pool depths and rules to prevent accidents. These safety measures enhance the overall experience for guests and reduce liability for hotel operators. Preventative maintenance and weekly water changes

Despite diligent water treatment, chemical sanitisers lose their effectiveness over time as contaminants accumulate. Changing the water in your hot tub or spa weekly, and ensuring you have a strict water management procedure for your swimming pool, is crucial to prevent unsafe levels of bacteria and ensure water clarity.

Only recently, a Japanese hotel manager apologised after it was revealed his staff only changed the water in their spa bath twice a year. Nor did they add chlorine to the water because the staff “disliked the smell”. As a result of this poor practice, the level of legionella bacteria found in the water was 3,700 times higher than the permitted level.

By following HSE Guidelines on cleaning and maintaining your spa-pool system, and changing the water on a weekly basis, you will keep your facilities clear of legionella bacteria and therefore prevent an outbreak of Legionnaires’ disease.