[The hygiene of drinking water after purification in practices and households]

According to the drinking water regulations which were modified in 1986 drinking water in FRG fulfills high standards. But there are still special needs for an additional processing of drinking water including --disinfection and removal of pyrogenous substances, --water softening, --removal of heavy metals and solvents, --removal of substances of bad taste. Methods actually used for processing of drinking water like disinfection, filtration, UV-treatment, exchange of ions, are described and the hygienic problems in connection with these methods are pointed out. Results of our own studies on water filtration systems and on contaminated water pipe lines in dental units are demonstrated. Our data obtained suggest that additional processing of drinking water should fulfill the following demands: --the need of processing should be confirmed strictly, --the methods used should be controlled according to their propagated effectiveness by independent specialists, --there should be a reasonable relation between operation costs and efficacy of processing system, --there should be no loss of quality of drinking water during processing with the risk of induction of infection or intoxication in man.