Microbiological Testing

Legionella bacteria occurs naturally within soil and water in the environment. Legionnaires disease (severe pneumonia) can be contracted by breathing in fine water droplets (aerosols) containing Legionella bacteria, which thrive in the warm humid environment of the lungs. People with strong immune systems exposed to Legionella bacteria are unlikely to become infected, however the risk of disease increases with age, a weakened immune system, and compromised lung health such as from smoking. Hospitalisation is common when Legionnaires disease is contracted. There exists the potential for permanent damage, and a small percentage of cases prove fatal.

Legionella can enter a cooling tower system through soil or water dispersion, where it can rapidly reproduce in the warm and moist environment it provides, particularly in the presence of nutrients and sunlight. Legionella bacteria can then escape the system within aerosols and travel significant distances to potentially enter a person’s respiratory system.

As part of your Risk Management Plan, microbiological testing must be conducted for Legionella and Heterotrophic Colony Count (HCC) in Victoria. Other states vary – please refer to Table 2 below.

HCC is considered an indicator of water quality in cooling tower systems – poor water quality can indicate an increased risk of Legionella growth. However there is no direct correlation between HCC levels and Legionella presence.

In Victoria, HCC samples are to be taken monthly at minimum, and Legionella sampling frequency is dependent on the Cooling Tower System overall Risk Category (A= highest risk to D=lowest risk), as detailed in Table 1 below;

Table 1. RECOMMENDED BACTERIA TESTING FREQUENCY

TESTING

FREQUENCY

RISK CATEGORY

A

B

C

D

HCC

Monthly

Monthly

Monthly

Monthly

Legionella

At least monthly

Monthly

Every 2 months

Every 3 months

Samples are to be taken from a dedicated sampling point that is away from the dosing point, and sent to an independent NATA accredited laboratory for testing. HCC results are received within 2 working days, and Legionella results within 7-10 days.

Bacteria concentrations must be managed within the following limits:

HCC: <200,000cfu/ml option for Victoria only.

HCC: <100,000cfu/ml rest of Australia.

Legionella: <10cfu/ml

In the event of a high HCC result or positive Legionella detection, then Protocols are initiated to disinfect and clean the cooling tower system and resampling undertaken. This is repeated until bacteria concentrations are below the specified limits. 


STATE MICROBIOLOGICAL TESTING & NOTIFICATION REQUIREMENTS

Applicable Legislation

Authorities

CT Registration

Microbiological Testing

Legionella Notification

VIC

Refer to CT Legislation

Department of Health

Yes

Dept Health

Routine testing for HCC (<200,000 cfu/ml) & Legionella (<10 cfu/ml) recommended by Department of Health Operational Program based on Risk Category within ‘Guidelines to Developing Risk Management Plans’ (pg.50).  This includes HCC & Legionella testing & disinfection requirements per the Public Health & Wellbeing Regulations 2009 (Section 7; Items 49 to 64).

Third positive Legionella Detection must be reported to Department of Health

1300 767 469.

NSW

Refer to CT Legislation

Local Council

NSW Health

Yes

Local Council

Monthly HCC and Legionella testing mandatory from January 2018.

Testing should comply with AS 3666; HCC/HPC <100,000 cfu/ml & Legionella <10 cfu/ml.

Amendments to the Public Health Regulation 2012 came into effect 1 January 2018 requiring the Local Government Authority to be notified when;

Legionella ≥1000cfu/ml

HCC ≥5,000,000cfu/ml

ACT

Refer to CT Legislation

ACT Health

Yes

ACT Health

No legislated private testing requirement.

Monthly monitoring for  HCC (<100,000 cfu/ml) & Legionella (<10 cfu/ml) recommended in ACT Code of Practice 2004.

ACT Health to be notified if Legionella ≥1000cfu/ml & HCC ≥5,000,000cfu/ml (per Code of Practice).

SA

Refer to CT Legislation

Local Council

SA Health

Yes

Local Council

No legislated private testing requirement.

Local authority required to test for Legionella at least annually under Regulations 2013; Section 15.

Notify Local Council within 24 hours when Legionella ≥1000cfu/ml (per SA Regulations 2013); Local Council in turn must then notify SA Health within 24 hours.

QLD

Refer to CT Legislation

Local Council

Queensland Health

Water Authority

No

No legislated private testing requirement.

Monthly testing of HCC (<100,000 cfu/ml) & 3 monthly Legionella (<10cfu/ml) testing recommended in the Guide 2013.

Legionella Detection Notification Form:

www.health.qld.gov.au/public-health/industry-environment/environment-land-water/water/risk-management/notify-legionella

From 1/02/2017, public hospitals with inpatients and private health facilities licensed under the Private Health Facilities Act 1999 are required to notify the Department of Health within 1 business day (using the Legionella Detection Notification Form) if the result of a prescribed test confirms the presence of Legionella in water used by the facility.

WA

Refer to CT Legislation

Local Council

Yes

Local Council

No legislated private testing requirement.

Minimum monthly testing of HCC (<100,000 cfu/ml) & 3 monthly Legionella (<10cfu/ml) testing recommended in the Code of Practice 2010.

None.

TAS

Refer to CT Legislation

Local Council

TAS Health

Yes

Local Council

Monthly HCC testing and 6 monthly Legionella testing, in accordance with AS/NZS 3666.3 (per Guidelines 2012 issued under the Public Health Act 1997).

None. Local Council prefer to be notified in the event of a positive Legionella detection, but it is not legislated.

The testing laboratory should notify TAS Health.

NT

Refer to CT Legislation

None

No

None.

None.

Legionnaire’s Disease is a Group A notifiable condition which requires immediate notification to the Australian Government Department of Health 1300 651 160, followed by written notification within 5 days.

Reviewed  March 2018