Legionella and water delivery systems

Overview

This page provides information to assist certain premises with a ‘water delivery system’ to develop a risk management plan and manage the risks associated with Legionella.

What is a ‘water delivery system’

ThePublic Health and Wellbeing Regulations 2019 Regulations say that a ‘water delivery system’ includes warm water systems, thermostatic mixing valve systems (TMV) and tepid loop systems. A water delivery system incorporates any shower plumbing, bath, pipes, water heaters, bathing facilities, water storage tanks or vehicle washing equipment used to store, deliver, transmit, treat or mix water.

Legionella risks in certain premises

Legionella has been detected in water delivery systems associated with showers and ice machines in hospitals and aged care facilities in Victoria. A car wash facility has also been linked to cases of Legionnaires’ disease.

Legionella is an organism that is ever-present in the environment and found in very low concentrations in the potable water supply. In the right environment, however, the Legionella bacteria can multiply and pose significant risks to the health of individuals exposed to the bacteria.

The risk of Legionella growth increases in water delivery systems that store water at temperatures between 20 °C and 60 °C.

People may contract Legionnaires’ disease if they are exposed to small droplets containing the bacteria, like those produced by high pressure hoses or showers. You cannot catch it from another person or by drinking contaminated water.

Legislation

The Regulations require certain premises, with water delivery systems to manage the risks associated with Legionella.

Section 82 of the Regulations requires that the responsible person must take all reasonable steps to manage the risks of Legionella in certain premises.

The ‘certain premises’ that the regulations apply to are:

1. where residential aged care services are provided; and
2. where health services are provided (but does not include health services provided at a day procedure centre);
3. that are prisons;
4. where impatient forensic mental health services are provided by the Victorian Institute of Forensic Mental Health; and
5. where commercial vehicle washes are operated.

The ‘reasonable person’ is any person who owns, manages, or controls the water delivery system.

Do I register a water delivery system?

There is no registration requirement for warm water delivery systems.

Requirements under the Regulations

Sampling program

Regulations do not require the testing of warm water systems, however, the department strongly recommends all high-risk facilities (hospitals, health and aged care facilities) periodically undertake a water sampling program to test for Legionella as part of a risk management approach. The Enhealth Guidelines for Legionella Control in Health and Aged Care Facilities assists facility managers to develop a sampling strategy as well as assess and manage the risks from Legionella.

Disinfection

It is strongly recommended that the responsible person must ensure that the water delivery system is disinfected, within 24 hours of receiving a report, that Legionella has been detected in a water sample taken from a water delivery system.

The department recommends using a chemical disinfection over a heat disinfection. However, if a heat disinfection is used it is very important to manage the risk of scolding.

Disinfection procedures are detailed in the Enhealth Guidelines for Legionella Control in Health and Aged Care Facilities.

Other recommendations

Following the detection of legionella in a water delivery system (TMV and Tepid Loop systems):

• Stop using all the showers in the system. That means stop using all the showers connected to the tepid loop or hot loop (for TMV systems) where Legionella was detected until the system has been disinfected.
• Inform the relevant people to ensure that there is a heightened surveillance for case of Legionnaires disease.
• Take a re-sample from the system 2-7 days after the disinfection.

Managing the risks of Legionella

Assessments of water delivery systems should not be restricted to shower systems and should include any system where the water in the system is at temperatures between 20°C and 60°C combined with the potential for a person to be exposed to respirable sized water droplets from the system.

To comply with the Regulations and to reduce the risk of Legionella in your warm water system, the department recommends that a Legionella risk management plan be developed for your water delivery system in line with Enhealth Guidelines for Legionella Control in Health and Aged Care Facilities. A risk management template has also been developed to assist with the process.

These guidelines are designed to be used for legionella control in warm water systems in hospitals and aged care facilities in Australia and New Zealand, however, they do not incorporate the Victorian legislative requirements.

The Public Health and Wellbeing Regulations 2019 describe the requirements for water delivery systems under the Victorian law. The Regulations should be consulted to ensure you are informed of your responsibilities.

Managing the risk of Legionella during COVID-19 response

There is an increased risk of Legionella growth in water delivery systems (e.g. shower systems) if they are not used, for example in communal facilities that have remained closed for an extended period. Stagnant (warm) water in unused systems may provide conditions that contribute to Legionella growth. If this has occurred, it is recommended that facilities review their water delivery systems and where required, carry out appropriate actions to manage the risks. The water system should be flushed as follows, prior to use:

• Flush hot and cold water through all points of use (e.g., showers, sink faucets)
• Flushing may need to occur in segments (e.g., floors, individual rooms) due to facility size and water pressure. The purpose of building flushing is to replace all stagnant water inside building piping with fresh water.
• Flush until the hot water reaches its maximum temperature.
• Care should be taken to minimize splashing and aerosol generation during flushing.

In general, it is recommended that showers that have been unused for 7 days or more are flushed before being used. Precautions should be taken to ensure people are not exposed to water droplets during the flushing process. Care should be taken to ensure droplets are not aerosolised. Wearing a P2/N95 mask may be appropriate in enclosed spaces where aerosol generation is likely.

More information is available in the EnHealth guidelines.

Responding to Legionella detection

Enhealth Guidelines for Legionella Control in Health and Aged Care Facilities outlines options for responding to detections of Legionella.

Commercial car washes – manage the risks associated with Legionella

A car wash facility in Victoria was linked to cases of Legionnaires’ disease.

The risks of Legionella growth in commercial car washes are increased when rubber hosing is used and when there is an absence of a biocide. Biocides are used to control harmful and unwanted organisms and microorganisms.

To manage the risks associated with Legionella in commercial car washes, the department recommends the following:

• not storing water at temperatures between 20 °C and 60 °C
• replacing warm water storage with instantaneous units
• replacing rubber hosing with poly tubing, metal tubing, or copper tubing
• regularly disinfecting the system with a chlorine-based disinfectant.

You can also obtain further information from the Australian Car Wash Association.