Seven Facts You Should Know About Water Hygiene

As temperatures rise during the summer months, the risk of Legionnaires’ disease increases. Employers, landlords, and facility managers must ensure their water systems are safe to protect public health and comply with legal obligations.

This comprehensive guide outlines seven critical facts about water hygiene that every duty holder should be aware of in 2025.

1. Legionella Remains a Significant Health Risk

Legionella bacteria thrive in water systems where temperatures range between 20°C and 45°C. Inhalation of contaminated water droplets can lead to Legionnaires’ disease, a severe form of pneumonia. According to the UK Health Security Agency (UKHSA), there were 604 confirmed cases of Legionnaires’ disease in England and Wales in 2023, the highest number recorded since 2017 .

These statistics underscore the importance of vigilant water system management, especially in facilities serving vulnerable populations.

2. Stagnant Water and Deposits Encourage Bacterial Growth

Stagnant water, particularly in dead legs or unused pipework, provides an ideal environment for Legionella proliferation. Deposits such as sludge, scale, or rust can further support bacterial growth. Regular system flushing and removal of redundant pipework are essential preventive measures.

Ensuring that water systems are designed to minimise stagnation and are regularly maintained can significantly reduce the risk of bacterial growth.

3. Certain Materials Can Promote Bacterial Growth

Some materials used in water systems, like rubber and certain plastics, can support bacterial colonisation. It’s important to assess and, if necessary, replace components made from materials that encourage biofilm formation. Consulting with water hygiene professionals can help identify and mitigate these risks.

Selecting appropriate materials for water system components is a critical aspect of preventing bacterial growth and ensuring long-term system integrity.

4. Aerosol-Generating Systems Pose Higher Risks

Systems that produce aerosols, such as cooling towers, showers, and spa pools, can disperse contaminated droplets over wide areas, increasing the risk of Legionella transmission. Implementing rigorous maintenance and monitoring protocols for these systems is crucial to minimise public health risks.

Regular cleaning, disinfection, and monitoring of aerosol-generating systems are essential to prevent the spread of Legionella bacteria.

5. Staff Training Is a Legal Requirement

Ensuring that maintenance staff and building managers are adequately trained in water hygiene practices is a legal obligation. Proper training helps in the early identification of risks and the implementation of effective control measures. GWT offers comprehensive Legionella Awareness Training to support organisations in meeting this requirement.

Training programs should be regularly updated to reflect the latest guidelines and best practices in water hygiene management.

6. Accurate Record-Keeping Is Essential

Maintaining detailed records of risk assessments, maintenance activities, and monitoring results is not only best practice but also a legal necessity. These records provide evidence of compliance and are invaluable during inspections or in the event of an outbreak.

According to the Health and Safety Executive (HSE), businesses with five or more employees must keep written records of:

• Risk assessments (kept for at least two years)
• Monitoring, testing, and inspections (kept for five years)

Even if your business is small, keeping accurate records is highly recommended.

7. Regular Risk Assessments Are Mandatory

Conducting regular Legionella risk assessments is a legal requirement under the Health and Safety at Work etc. Act 1974 and the Control of Substances Hazardous to Health Regulations 2002. Assessments should be reviewed periodically, especially when there are changes to the water system or its usage.

The HSE’s Approved Code of Practice (ACOP) L8 recommends that risk assessments be reviewed at least every two years or whenever there is reason to believe that the current assessment may no longer be valid.

Stay Compliant with GWT

Guardian Water Treatment specialises in helping organisations maintain safe and compliant water systems. Our services include risk assessments, system monitoring, staff training, and more. This is a complex area with a lot of legislation, so if you need any advice then please do get in touch with us.

You can find out more about the control of Legionella here.