How to Manage Legionella in Hot and Cold Water Systems

Legionella is a bacteria that can cause potentially fatal illness. For this reason, water systems must undergo a risk assessment and be maintained with regular inspections, water testing and water tank cleaning to ensure safe water quality and minimise legionella risks.

Read on to learn more about managing legionella in hot and cold water systems.

What Is Legionella?

Legionella is a type of bacterial commonly found in water. This bacteria can multiply in water between 20 and 45℃, contains nutrients and is stagnant. If a person ingests water droplets with viable legionella bacteria it can cause them to contract Legionnaires’ disease, a severe form of pneumonia.

While anyone can contract Legionnaires’ disease, it often proves more serious for the elderly, smokers or those with pre-existing conditions like diabetes, cancer or respiratory or kidney disease.

Risk Assessment

Conducting a Legionella Risk Assessment (LRA) is a legal requirement under the Health and Safety at Work Act 1974. Carrying out a legionella risk assessment will identify your system's risk of legionella growth. This will determine whether current measures are adequate or identify any improvements required to reduce the risk of legionella in your water system.

Temperature Control

Water services should be operated at temperatures that prevent legionella growth.

• 
  Cold water must be stored and distributed below 20℃.
• Hot water must be distributed at or above 50℃.
• Hot water storage cylinders must be stored at or about 60℃.

Hot water tanks should be checked monthly and cold water tanks should be checked bi-annually to ensure all water is stored and distributed at the correct temperature.

Water Testing

Periodic legionella water testing is vital to ensure proper compliance with legislation, including ACOP L8, HSG274 and HTM 04-01. The risk assessment will determine the frequency with which testing should be conducted. If any measures are deemed ineffective, testing should be carried out weekly until the system is under control and legionella is managed.

Water Tank Cleaning

Water tank cleaning helps to manage the risks of legionella. Water tanks and outlets should be effectively descaled every few months to remove nutrients that legionella bacteria can feed off.

Water Treatment

Copper and silver ionisation and biocide treatments can be used to treat legionella in water systems. This treatment can form part of a water management programme, including installation, maintenance and monitoring to ensure measures remain effective at mitigating legionella risks.

Caledonian Heating & Plumbing Ltd

At Caledonian Heating & Plumbing, as members of the LCA (Legionella Control Association), we can help your business ensure that your water systems are safe and compliant with current regulations. From legionella risk assessments to scheduling water testing and tank cleaning, we have a range of legionella management plans to suit businesses of all sizes.

For more information about our legionella services, get in touch today.