pros and cons copper silver ionization

Over a period of 10 years, Cachafeiro et al. (2007) studied copper silver ionization and showed that this technique is very effective in combating Legionella and biofilm, both in the short and long term. Other techniques, such as heat shock, failed in the long term (Sarjomaa et al., 2011; Lin et al., 2011). The advantage of copper silver ionization is that it is active throughout the entire drinking water installation (RIVM, 2012). As a result, the Legionella contamination is tackled entirely. However, a complete eradication of the Legionella bacteria is not possible. 

With a pH value above 8, the effectiveness of copper silver ionization decreases (Cachafeiro et al., 2007). Despite the fact that the ion-activity slows down under extreme basic conditions, the ions don’t shut down completely and will continue to do their work at a lower pace. The effectiveness of this technique is not dependent on temperature. However, with higher temperatures the technique works even faster (Cachafeiro et al., 2007). Also, copper silver ionization has a long residual effect (RIVM, 2012). Even if the system fails, the released ions will keep doing their work in the drinking water installation. Meaning, there is enough time to fix problems when they occur. 

Some microorganisms can develop a resistance to silver (Lin et al., 2011). Nevertheless, in the past 18 years, we have never experienced this. Our experience shows that when copper silver ionization is used, the installation is guaranteed to become Legionella safe. Therefore, we apply a money-back guarantee. A disadvantage of copper silver ionization is that it can leave a grayish residue behind (Sarjomaa et al., 2011). However, this only happens with 10% of the locations and often with old plumbing. The grayish residue is not unsanitary, but a natural reaction of lime, silver ions, and oxygen. We can provide cleaning detergents to easily remove it when necessary.

Ease of installation and maintenance is mentioned as one of the advantages of copper silver ionization (RIVM, 2012). One of the reasons for this is that this technique is not corrosive to your pipework. Also, no chemicals are required; meaning that valves and pumps are not affected. System maintenance will become even easier when the location is Legionella safe. Additionally, the ICA system is monitored online whereby the required maintenance can be closely followed without performing unnecessary activities. 

Copper silver ionization could also lead to cost reduction on energy as thermal treatment is no longer needed. Valuable water can be saved as flushing the pipes of stagnant water could be reduced to a monthly activity. The copper and silver concentrations might also be lowered. The KWR conducted research into lowering copper and silver concentration levels without losing effectiveness (Oesterholt, 2007). A location where the ICA system was installed and the recommended copper and silver concentrations were applied for one year could be reduced to 75% below the recommended values without increasing the Legionella count (Oesterholt, 2007).

  • 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)


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.