Cooling towers and warm water systems

NSW Health has strengthened public health legislation with a performance based (risk management) approach to the management of regulated systems, particularly cooling towers.

Owners and occupiers of these systems play a key role in preventing the growth and transmission of Legionella bacteria and protecting public health.

Legionnaires Disease is an infection of the lung caused by breathing in Legionella bacteria. While Legionella bacteria are naturally present at low levels in the environment, they have the ability to grow rapidly to dangerous levels in poorly managed systems.

Regulated systems must be installed, operated and maintained in accordance with the Public Health Act 2010, Public Health Regulation 2022, and AS/NZS 3666.

What are the different types of systems?

Water-cooling system: a cooling tower and its associated equipment and pipe work.


  • a device for lowering the temperature of water or other liquid by evaporative cooling
  • an evaporative condenser which incorporates a device containing a refrigerant or heat exchanger.

Warm-water system: a system designed to heat and deliver water at a temperature of less than 60ºC at each outlet point.


Responsibilities of the occupier

Installation, decommission, change of details

Owners and occupiers must notify Council following installation or decommission of a cooling water or warm water system, or where there is a change of occupier or particulars.

Council maintains a register of all water-cooling and warm-water systems installed/operating within the Shire, there is an annual administration fee associated with maintaining the property register - see fees and charges.

Any new systems must be registered with Council within one month of any such system being installed on the premises or if the details of the system have changed. The onus is on the owner/operator of the system to ensure that Council is provided with the necessary information. (Approved Form 6)

Requirements for water cooling systems (cooling towers)

Owners and occupiers of water-cooling systems must also comply with the following safeguards:

Prepare a Risk Management Plan (RMP) that assesses the risk of Legionella contamination - every 5 years (or more frequently if required).

An RMP document details best practices to effectively control the growth and transmission of Legionella bacteria and considers the risks that are unique to the cooling water system, and includes an action plan to identify and control risks. (Approved Form 1)

Engage an Independent Auditor to ensure the system is compliant with the RMP and Regulation - annually.

The auditor will assess whether the owner/occupier meets the actions, control strategies, monitoring and timeframes required by the RMP, and mandatory actions required by the Regulation. (Approved Form 2)

Provide certificates of RMP completion and audit completion to Council - within 7 days. (Approved Forms 1 and 2)

Test for Legionella and heterotrophic colony count - monthly.

Monthly sampling is key control strategy to reduce outbreaks particularly over the summer months where higher incidences of Legionella cases are observed. This includes an inspection, maintenance (including servicing), chemical analysis, and microbial testing. (Approved Form 3)

Notify reportable laboratory test results to Council (Legionella count = 1,000 cfu/mL or heterotrophic colony count = 5,000,000 cfu/mL - within 24 hours of receiving the result from laboratory;

Elevated Legionella count and hetrotrophic colony count are the main factors to be controlled in cooling water systems. High levels indicate a loss of effective microbial control and require urgent remedial action. (Approved Form 4)

Display a Council issued unique identification number on each cooling tower - within 30 days.

Unique identification numbers must be clearly visable and be A5 size (144mm x 210mm) or larger, made of durable material, and be prermanently attached to or painted on the cooling tower.

Council register

Council's Environmental Health Officers keep a register of regulated systems and may inspect systems, investigate reportable test results, investigate audit non-compliances, identify unregistered systems, and assist NSW Health during Legionnaires' disease outbreak investigations.

Registration and inspect fees apply, see fees and payments

Forms and guidelines

See Health NSW

More information

Council's Environmental Health Unit 02 6670 2400

NSW Health - Northern NSW Local Health District 02 6620 2100