Legionnaires disease investigation by local government
Legionnaires disease investigation by local government
This guidance note provides general information to aid Environmental Health Officer’s in investigating cases of Legionnaires’ disease within their jurisdiction. Legionella pneumophila (L. pneumophila) is a bacteria found in water, including scheme water. Legionella species are widespread in nature and can thrive in man-made water systems.
It is vital that potential exposure locations are investigated as an immediate priority and any potential sources identified are controlled as quickly as possible to prevent an outbreak. Other potential sources within 500m of the potential exposure location may still be worth investigating the bacteria can travel within water droplets on the breeze, for example, from a carwash or fountain.
It is difficult to pinpoint the exact source of a Legionnaires’ Disease outbreak with accuracy. The main aim of the investigation is to stop or reduce the impact of a potential outbreak by ensuring that possible sources of infection are controlled as quickly as possible.
Refer to the Investigating Legionnaires Disease guideline for local government (PDF 100KB) for further information.
Role of local government authorised officers
Local government Environmental Health Officers play a crucial role in investigating cases of Legionnaires’ disease, and have legislative powers to enforce compliance with the Health (Air-handling and water systems) Regulations 1994 (external site).
Environmental health investigations may involve:
- Assisting with mapping the investigation areas based on reviewing the movements of cases and where there is more than one case, defining area(s) of common outdoor or indoor exposure
- Reviewing satellite, aerial or other relevant imagery of the investigation area to identify potential sources and inspect as required
- Undertake physical inspections of building cooling towers.
- Undertake a physical inspection of other regulated systems, such as water systems, where exposures occur inside buildings, and there is indication that the system is not well maintained or no evidence of routine sampling.
- Review maintenance records where available and obtain samples if it is determined that the system is not maintained, routinely sampled or there were faults identified during the most recent service.
- Reviewing locations of potential sources within the vicinity, to identify possible sources of L. pneumophila.
- Obtain samples and review maintenance records where available.
- Where a system is visibly unclean with sediment or algae, or maintenance records are unavailable or out of date, obtain samples and advise owner to immediately clean, maintain and disinfect their systems.
- In the case of a potential outbreak, working with WA water treatment companies who undertake the regular maintenance and testing of cooling towers within the investigation area and ask to:
- contact their client list advising of outbreak within the area.
- advise clients to undertake emergency decontamination of systems.
- work with clients to carry out rapid cleaning and disinfection of those cooling towers they were contracted to manage.
- as laboratory results become available, advising owners whose systems tested positive to shut down and/or decontaminate systems where appropriate.
- undertaking follow-up inspections of sites with:
- systems that were visibly unclean
- systems with poor laboratory results.
- Liaising with patients in relation to the investigation into potential exposure locations, including their home.
- Provide advice to patients in relation to their concerns regarding the safety of potential water sources within their home.
Refer to the Reducing the risk of Legionella pneumophila in the home fact sheet (PDF 82KB) for further information.
Last reviewed: 02-12-2024