NSW cooling tower compliance guide

Written by David Supierz, Principal Chemist (BAppSc (Chemistry) (Hons), Master of Engineering Management) · Reviewed October 2026

In NSW, occupiers of buildings with cooling towers must register them with council, maintain a certified Legionella risk management plan, test monthly for Legionella and heterotrophic colony count, keep monthly reports, notify council of high results within 24 hours, and complete an independent audit every year.

Cooling towers can spread Legionella bacteria through the air if their water is not properly managed. To control that risk, NSW regulates every cooling tower and warm water system through the Public Health Act 2010 and the Public Health Regulation 2022. Local councils enforce the rules and can inspect systems and issue penalties.

What are the core obligations?

Register

Notify your local council of every cooling tower and warm water system on the premises. Tell council within 7 days of any change, such as a new occupier, a system modification or decommissioning.

Risk plan

Have a competent person carry out a risk assessment and prepare a Risk Management Plan before the system starts operating. Repeat it at least every 5 years, or every 12 months for high risk systems, and within 30 days if the current plan is no longer valid. Submit the certificate to council within 7 days of completion.

Test monthly

Have a qualified person sample and test each cooling tower system at least monthly for Legionella and heterotrophic colony count (HCC).

Report

Notify council within 24 hours of receiving a result of Legionella ≥ 1,000 cfu/mL or HCC ≥ 5,000,000 cfu/mL.

Audit

Have an approved independent auditor check compliance every year. The audit must be finished within 2 months of the end of each 12-month period. Submit the certificate to council within 7 days of completion.

Identify

Display the unique identification number issued by council on each cooling tower, within 30 days of receiving it.

Warm water systems: These must be registered with council, but the risk plan, testing, reporting, audit and ID requirements above apply to cooling towers only. Warm water systems have separate installation and maintenance rules.

Source: Public Health Regulation 2022 (NSW), NSW Health and City of Sydney guidance. This summary is general information. Check your council's requirements for your site.

What records do you need to keep?

• The current risk management plan and its certificate.
• Monthly Legionella and HCC laboratory results.
• Monthly reports (Approved Form 3).
• Service and dosing records from each site visit.
• Notifications of high results and the remedial action taken.
• Annual independent audit certificates.

How can Supierz Water help?

We prepare Legionella risk management plans, carry out monthly sampling and testing, complete your monthly Form 3 reports, manage your dosing program, review every laboratory result, respond quickly to high results and keep the documentation your risk management plan and annual audit rely on. Our chemists interpret your results rather than just recording them, so problems are caught before they become notifiable.

Cooling tower water treatment →

Questions