Domestic water:
Control Legionella safely in your building
Struggling with Legionella risk, biofilm and high energy use?
Legionella bacteria are a growing challenge in domestic water systems across Europe. The bacteria typically develop in lukewarm and stagnant water, where slimy biofilm quickly builds up inside pipes.
Exposure to Legionella bacteria can lead to Legionnaires’ disease, a severe and potentially fatal form of pneumonia. Infection occurs when tiny, contaminated water droplets from showers, taps or other installations are inhaled. The risk is highest in hot water systems.
Traditional control methods based on very hot water, flushing routines or hazardous chemicals are often energy-intensive, difficult to manage and not effective enough against biofilm inside the system.
Safer and more effective solution
Our DCW units produce a mild disinfectant on-site using only salt, water and electricity. The disinfectant Neuthox® is automatically dosed into the water system in small, controlled amounts to continuously protect against Legionella. It also removes and prevents biofilm where the bacteria would otherwise multiply rapidly.
Where Legionella control is critical
Large buildings have high Legionella risk due to complex water systems with long pipework, varying water temperatures and fluctuating water consumption. Our solution can be used to control Legionella and other harmful bacteria in both hot and cold water systems (where permitted).
Care facilities
Hospitals, care homes and healthcare facilities house vulnerable people who are at greater risk of serious illness from Legionella infection. Reliable water hygiene is therefore critical to protect patients and residents.
Residential buildings
Large residential properties often have complex water systems with long circulation loops and varying water use. This creates ideal conditions for biofilm and Legionella growth, which must be effectively controlled.
Hotels & spas
Hotels, resorts and spa facilities face increased Legionella risk due to fluctuating occupancy and complex water systems. Safe water is essential to protect guests and avoid reputational damage.
Sports centres & swimming baths
Sports centres and swimming baths often combine high humidity, aerosol exposure and extensive water systems. Continuous disinfection helps maintain stable hygiene and protects users.
What you gain with our Legionella solution
Protection around the clock
- Removes and prevents biofilm and harmful bacteria like Legionella
- Provides continuous protection throughout the water system 24/7
Better safety and health
- Uses a mild, water-based disinfectant
- Is highly effective – only low concentrations needed
Reduced energy use and costs
- Enables effective control at lower water temperatures
- Offers cost savings and a fast return on investment
Simpler operations
- Replaces temperature flushing routines and hazardous chemicals
- Fits into existing water installations and runs automatically
More sustainable solution
- Is produced on-site from just salt, water and electricity
- Saves energy and limits CO2 footprint
500+ installed DCW units help control Legionella in buildings
Remove biofilm – and stop bacteria from coming back
Biofilm is a thin, slimy layer of microorganisms that forms inside water pipes. It acts as a protective environment where Legionella and other harmful bacteria can grow and multiply. As long as biofilm remains in the system, bacteria can quickly return – even after thermal flushing or chemical treatment.
Our solution continuously disinfects the water and breaks down biofilm inside pipes. This removes existing contamination and helps prevent new biofilm from forming.
Before
After
Documented in a major national Legionella project
How to solve the growing Legionella problem without wasting energy
Over a three-year period, we participated in a major Legionella project in Denmark together with the Danish Technological Institute, Statens Serum Institut (under the Danish Ministry of Health) and other partners. The project resulted in proposed methods to better address the growing Legionella problem while at the same time reducing energy consumption – including our DCW solution, which was tested in field studies and demonstrated clear advantages.
Traditional Legionella control relies on high water temperatures, which is often problematic in practice and goes against the need to reduce energy consumption in buildings.
Field study: Complex Legionella problem solved within weeks
As part of the project, the DCW solution was tested in a large residential property near Copenhagen with seven buildings and almost 200 apartments. The property had persistent problems with Legionella and biofilm in its hot water systems.
The field study showed that the solution:
- Reduced Legionella levels to well below recommended thresholds within weeks
- Maintained stable water hygiene at temperatures below 50°C
- Eliminated the need for frequent thermal flushing
- Gave significant energy savings and a payback period of just 1½ years
- Postponed a costly renovation of the hot water system
Cases: Proven in complex and critical buildings
Hospital secures safe water for patients
A regional hospital has replaced temperature flushing routines with DCW units and achieved consistently clean and safe water for its patients. At the same time, the hospital has reduced energy consumption and simplified operations.
Read the full case
Hotel chain reduces risks and energy use
A UK hotel chain has proactively implemented the DCW solution across all sites to reduce energy use and avoid hazardous chemicals while maintaining safe, compliant water systems. The result is lower operational risks, significant cost savings and improved confidence.
Read the full caseLegionella in water systems – what you need to know
The harmful Legionella bacteria thrive in lukewarm and stagnant water from 20°C to 50°C and are commonly found in large buildings where domestic water systems are complex, and temperatures are often not optimal.
Exposure to Legionella bacteria can lead to Legionnaires’ disease, a severe and potentially fatal form of pneumonia – especially for elderly people, hospital patients and others with weakened immune systems. Infection occurs when tiny, contaminated water droplets from showers, taps or other installations are inhaled.
Effective and safe Legionella control is crucial to protect residents and users and comply with regulations.
FAQ about Legionella control and prevention
Why is Legionella difficult to control in large buildings?
Legionella bacteria develop at temperatures between 20°C and 50°C. In large buildings, it is difficult to maintain temperatures above 50°C throughout the hot water system and all the way to the taps. Especially areas such as long pipe runs, dead ends, shower hoses, storage tanks and poorly balanced circulation lines often create conditions where temperatures drop below 50°C, bacteria multiply and biofilm builds up.
Can high water temperatures alone prevent Legionella?
Water temperatures above 50°C limit Legionella growth, but they cannot remove the bacteria or the biofilm where they multiply.
Therefore, disinfection through thermal flushing is often carried out at 60–65°C, but newer studies indicate that temperatures around 70°C or higher may be needed to remove Legionella and biofilm throughout the system. Such temperatures are difficult to obtain in practice and increase energy use, scalding risk and limescale buildup in pipes and installations.
Going forward, it will become even more difficult and expensive to meet the temperature requirements, as the development is moving towards more low-temperature district heating and heat pumps to reduce energy consumption.
Why can Legionella return after flushing or chemical treatment?
One of the biggest challenges in Legionella control is biofilm inside the pipes. Biofilm protects bacteria and allows them to survive traditional treatment methods.
If the biofilm is not effectively removed and prevented, Legionella can quickly return after thermal flushing or chemical treatment.
Hypochlorous acid (HOCl) – the active substance in our Neuthox disinfectant – has proven highly effective against biofilm even at low concentrations because it breaks down the cell walls of microorganisms and bacteria. HOCl is estimated to be 70–80 times more effective than regular chlorine (OCl) at destroying bacteria.
How is Legionella monitored in domestic water systems?
Legionella is typically monitored through control measures such as water temperatures and disinfectant concentrations combined with water sampling and testing (rapid and/or laboratory-based).
We and our partners can help arrange Legionella assessment and testing of water systems.
For buildings using our solution, water quality can also be monitored through simple testing of Neuthox levels at taps and other sampling points to confirm that disinfection is active throughout the system.
What should you do if you discover Legionella in your water system?
When Legionella is detected, it is important to act quickly to reduce the health risk, identify the underlying cause and find the right solutions.
Typical steps include:
- Testing the extent of contamination in the system
- Reviewing control measures and performing a risk assessment
- Identifying corrective actions
- Cleaning the water system, including thermal flushing or shock disinfection
- Implementing long-term preventive measures to maintain safe water hygiene
We and our partners can advise you and help you get Legionella under control.
Technology and documentation
Interested in other application areas?
Looking for a safer way to control Legionella?
Get in touch to learn more about how our solution can help you.
