Legionellosis in buildings

Last updated: 15 March 2016

Building owners have certain responsibilities to prevent the growth of legionella bacteria in their buildings.

There are a number of formal mechanisms to ensure testing for legionella bacteria takes place on a regular basis. Some of these are governed by the Building Act, others by the Health Act.

Legionellosis is an infection caused by the bacterium legionella pneumophila. The disease has two distinct forms:

  • Legionnaires' disease, the more severe form of infection, which includes pneumonia
  • Pontiac fever, a milder illness.

Legionella bacteria can be found in both water and soil in the New Zealand environment and can breed in built environments, such as cooling towers.

To prevent the growth of the bacteria, cooling towers must be designed appropriately, treated and tested regularly.

Responsibilities of building owners

All buildings that contain a mechanical ventilation system must have a compliance schedule. The Compliance Schedule Handbook contains proposed inspection and maintenance procedures for these systems that can be detailed in a compliance schedule.

The compliance schedule sets out requirements for inspection, testing and maintenance. Building owners are responsible for ensuring mechanical ventilation systems are maintained and inspected according to the compliance schedule.

A notice to fix can be issued to you if you fail to comply with these requirements, with other possible fines and penalties.

Tests with results greater than or equal to 1000 cfu/ml should be notified within 48 hours to the local medical officer of health at the public service of the district health board.

Functions of MBIE

MBIE administers the Building Act 2004 and associated regulations, as well as ensuring buildings are safe and healthy under the Act.

For buildings with cooling towers, provisions include:

  • the building warrant of fitness and compliance schedule regime
  • offence provisions
  • territorial authorities setting policies on dangerous and insanitary buildings.

If a workplace is identified as being a possible source of legionella bacteria, MBIE will work with Public Health and other agencies such as territorial authorities to investigate specific risks that may have contributed to the growth of the bacteria.

In serious cases, action may be taken under the Health and Safety in Employment Act to:

  • improve the health and safety of the workplace
  • prohibit dangerous activities
  • or prosecute.

Some cooling towers are not covered by the building warrant of fitness. For example, those associated with a manufacturing process are covered under the Health and Safety in Employment Act 1992 administered by MBIE and are expected to comply with AS/NZS 3666 Parts 1, 2 and 3.

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: