Legionella are bacteria that live in water and are found naturally in lakes and rivers. If the temperature of the water increases above 20°C the legionella bacteria will multiply, increasing in number. They grow and spread in human-made building water systems such as showers, cooling towers, air conditioning, spa pools and water features, among other things. Legionella bacteria can be spread through the water forming into a fine spray which can then be inhaled. This can lead to a type of pneumonia, called Legionnaires’ Disease which is a serious, potentially fatal disease. Some people are more at risk of catching the disease than others, these include

  • People over the age of 50
  • Smokers
  • People with chronic lung disease
  • People with a weak immune system (or those taking drugs to supress their immune system)
  • Those with underlying illness such as kidney disease or liver failure

  1. The temperature of the water is key to controlling legionella bacteria. Cold water must be below 20°C and hot water must be stored above 60°C.
  2. Outlets must be regularly used, stagnant water allows biofilm (microbial slime) to build up. Biofilm is an ideal environment for legionella bacteria to grow and can grow on any surface that is continuously exposed to moisture.
  3. Chemicals can be used to control legionella bacteria. Chlorine and bromine are effective at killing bacteria and can be added to water systems. Chlorine is used in domestic systems while bromine can be used in industrial systems. Other chemicals such as hydrogen peroxide can also be used.
  4. Physical methods of removing bacteria are also used in bacterial control. UV filtration or Point of Use filters can be used as part of a larger bacterial control strategy.

How can I control legionella bacterial?

It is a legislative requirement to control the risks from legionella bacteria in water systems. Legionella risk assessments must be carried out and they must be more than a simple tick box exercise. They must be comprehensive and suitable for the building in question and must cover all water systems present on site and not just domestic water systems.

A control scheme must be written to set out how the water systems will be managed. This must include which methods of legionella control are to be used, how use of these controls will be checked and what records need to be kept. This control scheme should be audited regularly to make sure that legionella controls are being met.

Whether you need Legionella Risk Assessments, a compliance audit on your services, a complete water hygiene service, or have specific legionella management and control requirements, Green Water Treatment Solutions, (GWTS) can provide you with the service you need.

As an independent consultancy GWTS can offer clients a full range of solutions to meet legionella risk controls. With a diverse range of clients, across the UAE, we can provide you with a bespoke service giving you complete peace of mind. Our team of experienced and knowledgeable consultants have worked on a variety of complex and simple water systems within healthcare, commercial and industrial buildings.

Legionella risk assessments

GWTS offers a complete range of individually designed solutions to ensure you comply with the requirements of the OSHAD COP 12.0 – Prevention and Control of Legionnaires Disease. This Code of Practice requires all building owners or facility managers to have a Legionella Risk Assessment for their site if they have any facilities that uses, stores or disseminates warm water. GWTS will provide a comprehensive report referring to the ASHRAE and HSE ACoP L8 as well as other best practice guidance.

Our risk assessments have been developed with our clients in mind, providing you with an independent, detailed and easy to understand working document.

Legionella compliance audits

Compliance audits are your reassurance that your legal requirements are being met reducing your risks of enforcement action or financial penalties. A compliance audit will review your company policy and management procedures and also confirm that any maintenance regime required to maintain the health of your water systems is suitable and being fully carried out, and that you comply with legislative requirements.