Legionella in Water System
Could your hot water system be at risk?
Call 0800 278 296 to protect your home and health
Could your water system be at risk?
Legionella is not usually contracted by drinking water, but by breathing in contaminated water droplets, such as from showers, taps or other water systems. This means your water can look completely clean — while still posing a risk through everyday use.
In homes with hot water systems, long pipe runs or low usage, the risk can increase without you knowing.
What is Legionella in water systems?
Legionella is a type of bacteria commonly found in natural water sources that can grow inside man-made water systems such as plumbing, hot water cylinders and pipework. When conditions are right, the bacteria can multiply and spread through fine water droplets, creating a potential health risk.
At Aqua Works, we help identify these risks and ensure your water system is properly managed and protected.
A hidden risk in your water system — With serious consequences: Legionella!
Understanding the risk of Legionella in your water system
How does Legionella get into your system?
Legionella bacteria are naturally present in water and can enter plumbing systems through the water supply. Once inside, they can grow and spread in:
- Showerheads and taps
- Hot water cylinders
- Pipework and storage systems
The most common way people become infected is by inhaling contaminated mist from these systems.
Why Legionella is a risk in homes and baches
Legionella grows best in warm, stagnant water, particularly in temperatures between 20°C and 50°C.
This makes typical plumbing systems a potential risk, especially when water is not regularly circulated or properly managed.
Homes, holiday houses, baches and buildings with low water usage are particularly vulnerable.
When should you be concerned?
You should be concerned if your system has:
- Low or inconsistent hot water temperatures
- Areas of low flow or unused pipework
- Long periods of stagnation (e.g. empty homes)
- Older or poorly maintained systems
In many cases, the risk is not visible and only becomes apparent once a problem develops.
What DOESN’T work
Many people assume basic water treatment or occasional flushing is enough — but Legionella is a system problem, not just a water quality issue.
Common approaches that don’t provide reliable protection include:
- Turning up hot water temperatures without system control
- Flushing pipes occasionally instead of managing flow
- Relying on basic filtration alone
- Ignoring low-use or stagnant areas of the system
Legionella can grow within plumbing systems and biofilms, making it difficult to control without a properly designed approach.
Health risks associated with Legionella
Legionnaires’ disease, a serious lung infection (pneumonia)
Cough and shortness of breath
High fever
Muscle aches and fatigue
Headaches and confusion
The illness can become severe if not treated early, particularly for older adults or those with underlying health conditions.
How Aqua Works manages Legionella risk in your water system
Legionella control requires a system-wide approach, not just a single device.
At Aqua Works, we assess your entire water system and implement solutions that manage the conditions where Legionella grows.
STEP 1 — Assess your water system
Legionella risk cannot be seen and is often linked to how your system operates — not just the water itself.
We assess your hot water system, pipework, temperatures and usage patterns to identify conditions where Legionella can grow, such as stagnation, inconsistent temperatures or low flow areas.
STEP 2 – Control temperature, flow and stagnation
Legionella bacteria multiply in warm, stagnant water and can survive within biofilm inside pipes and system components. Controlling these conditions is critical and includes:
- Maintaining correct hot and cold water temperatures
- Preventing stagnation and ensuring proper circulation
- Managing system design to eliminate dead ends and low-flow areas.
STEP 3 — Implement a long-term system solution
Effective Legionella control requires a combination of system design, treatment and ongoing management.
At Aqua Works, we implement tailored solutions that include system upgrades, disinfection technologies such as UV water filtration or ozone tank treatment, and adjustments to ensure your system operates safely and consistently.
STEP 4 — Ongoing monitoring and maintenance
Legionella risk does not disappear after installation.
Without proper monitoring and maintenance, conditions can return and bacteria can regrow within the system.
We provide ongoing support (UV water filter service or Ozone tank system service) to ensure your system continues to operate safely and remains under control over time.
Your water system could be putting you at risk
The only reliable way to manage this risk is through proper system assessment, control and ongoing maintenance.
FAQ about Legionella in your water system
Can you get Legionella from drinking water?
Legionella is not usually contracted by drinking water, but by inhaling contaminated droplets from showers or water systems.
Is Legionella common in NZ?
Legionella bacteria are commonly found in the environment, including water and soil, making system management essential.
What temperature kills Legionella?
Legionella bacteria are killed at higher temperatures, typically above 60°C, but system design is required to ensure consistent control.
How do I know if my system is at risk?
A professional system check is the only way to identify risk conditions such as temperature issues or stagnation.
Where does Legionella grow?
It grows in warm water systems such as pipes, tanks, showers and hot water systems.