The Prevention of Legionellosis in New Zealand: Guidelines for the Control of Legionella Bacteria

These guidelines assist those concerned with legionella, including public health officers, territorial local authorities, building owners, air conditioning engineers, employers and others dealing with maintenance of buildings.

The guidelines aim to increase awareness of the hazards associated with Legionella and provide a guide for managing the risk of other proven sources of Legionella such as garden soils, compost and potting mixes, as well as recreational water sources (eg, spa pools).

Part 2 of the guidelines provides advice on the follow-up of cases of legionellosis to improve the reporting and investigation of cases of legionellosis. 

2024 and 2025 revisions

These guidelines update and supersede Prevention of Legionellosis in New Zealand: Guidelines for the Control of Legionella Bacteria (Ministry of Health, 2011).

The 2024 revision updated the scientific evidence and surveillance data and technical content of the guidelines, and also updated the operational advice on cleaning and disinfecting water systems to reflect the types of plumbing systems currently in use. This April 2025 version also clarified expectations around the investigation of sporadic cases.