Plumbing-led Legionella control — hot water temperature management, warm-water system maintenance, dead-leg removal, system flushing and NSW cooling-tower compliance. One licensed partner for your water-safety obligation.
Legionella pneumophila is a waterborne bacterium that causes Legionnaires' disease — a severe and sometimes fatal form of pneumonia. It does not spread person-to-person; it spreads when people inhale fine water droplets (aerosols) contaminated with the bacteria. Showers, cooling towers, spa pools, decorative fountains and any system that creates a mist from stored water are potential transmission sources.
The bacterium thrives in water between approximately 25°C and 45°C. Below 20°C it is dormant. Above 60°C it is killed. This temperature relationship is why plumbing is the primary control mechanism — if your hot water is stored at the right temperature and your system has no stagnant sections sitting in the growth range, Legionella cannot colonise.
Hot water must be stored at a minimum of 60°C to suppress Legionella. But water at 60°C will scald a person in seconds, so it cannot be delivered to outlets at that temperature — particularly in facilities serving children, the elderly or the unwell. The solution is a thermostatic mixing valve (TMV), which stores water hot for safety against bacteria and delivers it at a controlled 43.5°C to 45°C for scald protection.
This is why Legionella control and TMV testing are inseparable, and why both must be maintained together.
Hot and cold water temperature control — verifying storage stays at or above 60°C and that cold water stays cold, so neither sits in the Legionella growth range.
Warm-water-system management — the highest-risk systems, maintained with monitoring, flushing and design review.
Dead-leg identification and removal — eliminating the stagnant, capped-off pipe runs where bacteria breed.
System flushing and recommissioning — flushing low-flow runs and infrequently used outlets, and recommissioning systems after treatment or extended vacancy.
TMV and backflow integration — coordinating temperature control with TMV testing and backflow prevention under one maintenance plan.
Documentation and reporting — clear records of every temperature reading, flush and test, ready for an audit or an authorised officer.
If your facility operates a cooling tower, it falls under the NSW Legionella Control Regulations that came into force in 2018, which impose specific duties on the occupier. Each cooling-tower system must have a risk management plan, undergo an independent annual audit, be registered with the local authority and display its unique identification number, complete a monthly compliance report, and undergo monthly laboratory testing — with any high Legionella result reported to the local authority within 24 hours.
We coordinate the plumbing-side obligations of this regime and work alongside your water-treatment provider so nothing falls between the two.
Legionella control is not a stand-alone task — it is the product of correct temperatures, sound system design, working TMVs, protected supply and disciplined flushing. O'Brien delivers all of those under one licensed contractor and one commercial maintenance plan, rather than leaving you to coordinate a Legionella specialist, a TMV plumber and a backflow tester separately. One partner, one schedule, one set of records.
Legionella is suppressed when hot water is stored at a minimum of 60°C. Because water at that temperature can scald, it is delivered to outlets through a thermostatic mixing valve at a safe 43.5°C to 45°C. Water between roughly 25°C and 45°C is the danger zone where Legionella grows.
A dead leg is a section of pipe — often a capped-off or rarely used run — where water sits still. Stagnant water in the Legionella growth-temperature range is an ideal breeding site, which is why identifying and removing dead legs is a core part of plumbing-side Legionella control.
Yes. Warm-water systems carry the highest potential for systemic Legionella colonisation because so much of their pipework sits in the bacterial growth range. They require closer monitoring, flushing and design review than standard hot-water systems.
Under the NSW Legionella Control Regulations, cooling-tower systems require a risk management plan, an independent annual audit, registration and a displayed unique identification number, monthly compliance reporting, and monthly laboratory testing, with high results reported to the local authority within 24 hours.
Yes. We integrate temperature control, warm-water management, TMV testing and backflow prevention into a single commercial maintenance plan, so one licensed partner manages your whole water-safety obligation.
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Protect your residents, guests and reputation with plumbing-led Legionella control.