As a follow-up on the article on the effectiveness of thermal treatment, this week we will discuss the effectiveness of copper silver ionization. In the scientific literature study of the RIVM (Dutch National Institute for Public Health and the Environment), the effectiveness of various Legionella prevention techniques are discussed. We have summarized the findings concerning the technique copper silver ionization.

In this article, we’ll discuss the pros and cons of copper silver ionization; on what does the effectiveness of this technique depend on; what the most effective Legionella prevention technique is according to the PWN and the GGD; and, we’ll showcase two international hospital cases.

RIVM rapport on the effectiveness of copper silver ionization

In the RIVM Report (2012) and the presentation on alternative techniques by Alvin Bartels at the ISSO congres (2013), copper silver ionization is cited as most effective. It is an efficient method for long-term control of the Legionella bacteria (Cachafeiro et al., 2007). Additionally, Lin et al. (2011) concluded in their review that copper silver ionization is the most effective technology to control Legionella. 

Pros and cons of copper silver ionization
  • effective for long and short term

  • active in the entire drinking water installation

  • removes biofilm

  • longer residual effect

  • technique is not affected by temperature

  • proven most effective Legionella control technique

  • less maintenance

  • non-corrosive for the pipework

  • concentrations of Cu and Ag can be lowered without losing effectivity

  • less intensive flushing activities

  • may leave a grayish residue behind

  • some microorganisms can build-up a resistance against silver

  • the ion-activity slows down under extreme basic circumstance (pH > 8)

Read here the scientific analysis of the RIVM about the pros and cons of copper silver ionization.

Effectiveness of copper silver ionization – depends on ion concentration and dead pipelines

The effectiveness of the technique depends on the used Cu and Ag concentrations and the amount of dead pipelines (RIVM, 2012). To guarantee safe operations of the system, it is important to monitor the ionization process 24/7. A reliable copper silver ionization party can completely take care of the online monitoring and associated system maintenance. They will also map the number of dead pipelines and give appropriate advice. Contact us for more information about the service and management options at ATECA.

What do the PWN and the GGD consider to be the most effective Legionella control technique?

When Legionella is not controllable with regular techniques, copper silver ionization is the most effective alternative method according to the PWN. “(…) because this technique has a very long residual effect and the system can be properly adjusted and monitored remotely. Due to the residual effect, this technique still offers Legionella control even if the system fails. ”(Quoted in RIVM, 2012). GGD, on the other hand, does not mention a preferred Legionella control technique. According to them, the best control technique is one that requires as little maintenance as possible and is independent of human actions. One of the advantages of copper silver ionization is the ease of installation and maintenance of the system (RIVM, 2012). The GGD also cited that site managers often do not closely observe risk analysis and management plans (RIVM, 2012). That is why ATECA offers a full service and management package to reduce the pressure on the manager and completely take care of the Legionella problem.


Bartels, A. (2019). Effectiviteit van beheerstechnieken voor legionella in drinkwaterinstallaties. ISSO-congres Alternatieve technieken

Cachafeiro SP, Naveira IM, García IG. 2007. Is copper-silver ionisation safe and effective in controlling legionella? J Hosp Infect. 67:209-216.

Chen YS, Lin YE, Liu YC, Huang WK, Shih HY, Wann SR, Lee SS, Tsai HC, Li CH, Chao HL, Ke CM, Lu HH, Chang CL. 2008. Efficacy of point-of-entry copper– silver ionisation system in eradicating Legionella pneumophila in a tropical tertiary care hospital: implications for hospitals contaminated with Legionella in both hot and cold water. J. Hosp. Infect. 68:152-158.

Lin YE, Stout JE, Yu VL. 2011. Controlling Legionella in hospital drinking water: an evidence-based review of disinfection methods. Infect Control Hosp Epidemiol. 32:166-73.

Mòdol J, Sabrià M, Reynaga E, Pedro-Botet ML, Sopena N, Tudela P, Casas I, Rey-Joly C. 2007. Hospital-acquired legionnaires disease in a university hospital: impact of the copper-silver ionization system. Clin Infect Dis. 44:263-265.

Oesterholt F. 2007. Optimalisatie van koper/zilver-ionisatie in leidingwaterinstallaties bij de Rijksgebouwendienst. KWR rapport nr. 07.042

RIVM Rapport 703719078. (2012). Effectiviteit van beheerstechnieken voor legionella in drinkwaterinstallaties.

Sarjomaa M, Urdahl P, Ramsli E, Borchgrevink-Lund CF, Ask E. 2011. Prevention of Legionnaires’ disease in hospitals. Tidsskr Nor Laegeforen. 131:1554-1557.