Regulatory frameworks for Legionella control in Australia: a scoping review of public health legislation and policy with New Zealand comparison

Public health regulation in Australia operates through complex regulatory frameworks which includes Acts, Regulations, Codes of Practice, Guidelines and policy directives. While the public health significance of Legionella control is well recognised, limited research has examined how regulatory instruments collectively constitute the framework for Legionella management or alignment with international guidance. ISO 31000:2018 Risk Management – Guidelines-provide a structured approach to risk identification, assessment and treatment, emphasising context specific application and continual improvement. This aligns closely with the World Health Organization (WHO) Water Safety Plan approach, adopted across Australian jurisdictions to manage water related hazards. National standards, including AS/NZS 3666, complement this guidance by specifying technical requirements for the prevention and control of Legionella in building water systems. This review examines regulatory frameworks for Legionella management across Australia with New Zealand included as a comparator. A comprehensive search of the AustLII database was conducted to identify the regulatory components relevant to Legionella management across Australian states and territories. Additional policy documents were identified from previous literature reviews and targeted searches of state and territory health department websites. Comparable regulatory and guidance documents from New Zealand were included for analysis. Ninety-one documents, including eleven Acts and regulations, were reviewed and assessed for consistency with WHO guidance on Legionella prevention and control. Substantial variation was observed across jurisdictions in regulatory scope, system registration requirements, and the structure and frequency of risk assessments. Differences were also identified in microbiological monitoring requirements, sampling frequencies, threshold limits, regulatory responses to elevated heterotrophic colony counts and Legionella detections, and prescribed decontamination protocols. Management of high-risk system components, including thermostatic mixing valves, dead legs, and aerosol-generating devices varied. Notwithstanding these differences, jurisdictions consistently recognised Legionella as a significant public health hazard, referenced AS/NZS 3666, and emphasised risk-based management and routine monitoring. Comparative analysis of regulatory frameworks demonstrates significant disparities in public health legislation and policy related to Legionella prevention. These findings demonstrate the need for evidence informed policy and national coherence to strengthen Legionella control and better protect public health.