Legionella Control Strategies

Choosing the Optimal Solution for Supplemental Disinfection

Complex building water systems, lack of potable water disinfectant residuals and ideal temperatures for the growth of Legionella continue to drive the need for supplemental disinfection across the healthcare and hospitality markets. Nalco Water has developed unique onsite generation technologies for both cold and hot water systems, which have distinct and independent challenges. These systems are controlled and monitored by our award-winning 3D TRASAR™ Technology for Supplemental Disinfection includes our 24/7 Ecolab Global Intelligence Center.

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Managing any supplemental disinfection system may require a permit for the treatment of drinking water. Nalco Water offers years of experience in permitting and operation of numerous applications across varying water qualities. We offer two comprehensive onsite generation systems and service programs to ensure proper control of the disinfectant application. Using your Water Management Plan as a guide, we will recommend the right system, the right chemical, and the right application strategy that will most effectively reduce your risk.



Nalco Water has the first chlorine dioxide supplemental disinfection program approved by the U.S. Environmental Protection Agency to reduce Legionella in water.  LegionGuard can serve as an important part of an overall program for the reduction of Legionella bacteria in potable water systems.

  • Lab tests have shown that LegionGuard reduces Legionella by 99.99% in water
  • NSF certified
  • Single precursor for Envirox™: Electrolytic Chlorine Dioxide Generation


Onsite electro-chemical or electrolytic chlorine generation is ideal for hot water systems. By using common salt as a precursor, our technology generates chlorine onsite for the continuous treatment of a hot water system, or it can be used to remediate the system as a hyperchlorination step. Electrolytic chlorine also contributes less chloride than liquid chlorine which limits corrosion caused by chlorides.

  • Ideal for hot water systems
  • 3D TRASAR control and 24/7 monitoring with alarming
  • NSF certified, UL/CSA listed, NEC/NFPA compliant
  • Safe, stable, non-hazardous precursor (salt)
  • Direct measure of chlorine residual
Envirox Chlorine Dioxide Generation Cabinet


Onsite electro-chemical or electrolytic chlorine dioxide generation is ideal for cold water systems but can also be used for the entire potable water distribution system when the system is small and less complex. By understanding oxidant demand, temperature, water usage and overall system design, you can determine proper treatment schemes.

  • Ideal for cold water systems
  • 3D TRASAR control and 24/7 monitoring with alarming
  • NSF certified, UL/CSA listed, NEC/NFPA compliant
  • Single precursor system using no acid
  • Built-in softener to handle most water qualities
  • Direct measure of chlorine dioxide residual
A picture of the Ecolab Global Intelligence Center (EGIC) in Pune, India


Nalco Water’s industry-leading 3D TRASAR Technology is designed to help you manage the safety of your water supply used by patients, employees, and guests. Our dedicated Ecolab Global Intelligence Center is a team of degreed engineers who respond to alarms and troubleshoot your system(s) to ensure compliance.

  • NSF certified, UL/CSA listed, NEC/NFPA compliant
  • State-of-the-art feed and control system
  • 24/7 remote monitoring and management
  • Continuous trending of disinfectant residuals
  • Installation and service provided by a Nalco Water Certified Service team