Legionella Control

Many water systems require routine treatment, cleaning and disinfection to meet industry standards, Health Department regulations, Codes of Practice and to mitigate risks associated with Legionella. SAS Water provides comprehensive Legionella control programs and associated services, ensuring the highest degree of pathogen risk management for our Clients.


Cooling Towers

The safety of our people, clients and the general public is of the highest priority at SAS Water and we have comprehensive policies in place to monitor and control such risks. Industrial risks can be real and significant to public health through illness or death – as periodically seen through Legionnaires' disease outbreaks. As such we not only meet regulatory requirements but implement additional safeguards to ensure maximum risk mitigation.

Legionella is a naturally occurring bacteria found in soil and water bodies and cooling towers provide an ideal environment for its proliferation, along with the generation of aerosols available for inhalation, which can propagate a Legionnaires' disease outbreak. To mitigate this risk:

    1. It is critical a chemical program with proven biological efficacy against Legionella is implemented and diligently maintained.
    2. This must be augmented, typically 3 or 6 monthly, with a thorough cleaning and disinfection regime to remove dirt, debris, nutrients and bioflim from the cooling system in addition to providing routine sanitisation.
    3. Regulatory microbial testing must also be performed for Legionella and Heterotrophic Colony Counts (HCC) to ensure the required performance and compliance is achieved - typically this is performed monthly with requirements being <100,000cfu/mL for HCC and <10cfu/mL for Legionella, however this varies with local State regulations and the cooling tower risk category.
    4. SAS Water also designs, builds, installs, commissions and maintains sidestream filtration systems for cooling towers. Sidesteam filtration systems are effective at reducing dirt and nutrient loadings in the cooling water, allowing increased biocidal efficacy, improved microbial control and less likelihood of positive Legionella detections. Accordingly in line with engineering best practice and a proactive risk management plan, we recommend the installation of sidestream filtration on all cooling towers.

Any Legionella control program however, is only as good as the level of field service provided. Our team of technicians are highly trained and well equipped to work under hazardous conditions with a primary focus on the safety of all parties involved. All are fully qualified, aware of AS/NZS 3666:2011 and associated standards and certified for working in confined spaces and cleaning at elevated heights.


TMVs & Tempered Water Systems

Although Legionella disinfection can be achieved thermally as elevated temperatures above 63OC is lethal to Legionella, warm water systems and those utilising thermostatic mixing valves, which are often employed in hospitals, healthcare and aged care facilities, can harbour and allow Legionella to proliferate, especially when they are "seeded" by raw water containing positive Legionella counts. 

Heated water supplied from new heated water services must be delivered to ablutionary fixtures at a temperature that reduces the likelihood of scalding. In childhood centres, nursing homes, primary schools and the like, the delivery temperature to sanitary fixtures used primarily for personal hygiene purposes must not exceed 45OC. In other buildings, the maximum temperature delivery to sanitary fixtures used primarily for personal hygiene purposes must not exceed 50OC.

The Plumbing Code of Australia forms part of the Plumbing Regulations 2008. which specifies the objectives and performance requirements related to the installation of heated water services, and AS/NZS3500.4 requires that stored heated water be at no less than 60OC. Despite these regulations, it is not uncommon to see poorly designed &/or maintained systems being "Legionella positive" and indeed contributing to Legionnaires' disease outbreaks seen both in Australia and globally.

SAS Water is well equipped to perform audits of both new warm water system designs or facilities with existing systems to eliminate Legionella related health risk for all stakeholders, in addition to performing the required microbiological testing, provision of equipment and routine maintenance. Best practices include:

  • Implementation of a tailored testing regime.
  • Properly design & implemented raw water chlorination.
  • Secondary raw water and warm water system chlorination.
  • Incorporation of suitable filtration systems where necessary.
  • Avoiding the use of UV disinfection technology.
  • Routine hot water flushing &/or super-chlorination as required.
  • Implementation of a suitable TMV maintenance program, with replacement when required.


Other Services

SAS Water performs risk management consultation and microbiological testing services to identify high risk areas; a necessity for implementation of a best practice solution for your facility and in dealing with pathogen risk management. In addition to this and performing precommission cleaning of new assets and acid descaling services for boilers and heat exchange equipment, SAS Water provides for the methodical cleaning and disinfection of the following water sources:

  • Pits
  • Potable water tanks
  • Rain water tanks
  • Waste treatment plants