Managing cooling water systems

Cooling water systems must be managed safely in order to prevent the growth and transmission of Legionella bacteria. Infection may cause Legionnaires’ disease, a serious and potentially life-threatening condition.

The Public Health Regulation 2022 requires a performance based or risk management approach to managing cooling water systems. This approach allows each system to be managed according to its risk of Legionella contamination.

Building occupiers are required to ensure that there are six key safeguards in place for their cooling water systems:

1. Risk assessment of Legionella contamination, documented in a Risk Management Plan (RMP) – every five years (or more frequently if required).
2. Independent auditing of compliance with the RMP and Regulation every year.
3. Providing certificates of RMP completion and audit completion to the local government authority.
4. Sampling and testing for Legionella and heterotrophic colony count every month.
5. Notifying reportable laboratory test results (Legionella count ≥1000 cfu/mL or heterotrophic colony count ≥5,000,000 cfu/mL) to the local government authority.
6. Displaying unique identification numbers on all cooling towers.