Guidelines
Copper silver ionization technology is recognized by the WHO, the U.S. Environmental Protection Agency (EPA) to control Legionella within potable water distribution networks found in hospitals, hotels and other large type facilities. The level of ions generated has been reported to be usually below EPA Safe Water Drinking Act Lead and Copper Rule limits. EPA-approved levels of copper or silver in potable water are 1.3 ppm (Cu) and 0.1 ppm (Ag). Suboptimal timing of specimen shipment for testing at reference laboratories may contribute to silver concentration above recommendations. Industry leaders who manufacture copper silver ionization technology recommends copper concentration of 0.4 to 0.8 ppm and silver at 40 to 60 ppb, as compliant with EPA drinking water standards.
The British Health and Safety Commission regulates U.K. ionization, advising regular system monitoring to ensure ions reach all water circuits. Also, copper in drinking water is limited to 2 ppm (mg/L) by the European Community whereas Legionella control only requires 0.4 to 0.8 ppm in concentration...well below the permissible limits. Headquarters (ECH) in Brussels, Belgium, and silver is not prescribed by the ECH.
USA maximum copper limits for potable water is set at 1.3 ppm whereas EU limitations is 1.0 ppm. Silver limits in the USA is set at 0.1 ppm (100 ppb) yet the EU does not have any guidelines for ionic silver concentrations.
Recent Developments
The EU commission have recently introduced a directive that effectively bans the production and use of Copper silver ionisation units by banning the use of elemental copper. No justification on health grounds for this ban has been shown and the European industry is now trying at great cost to prove to the commission that such systems are not hazardous
Read more about this topic: Copper-silver Ionization