The year 1925 brought an update to the drinking water standards. PHS first instituted a limit for bacteriological counts. They also set limits for physical and chemical levels for lead, copper, zinc and excessive soluble minerals. These revisions spelled out guidelines for methods of bacteriological sampling and set maximum permissible concentrations for such substances as arsenic, fluoride, lead, selenium and copper. The standards were limited in ensuring safe drinking water for the public.
Concern arises over water quality.
By the 1960s, economics, population and industrial growth increased the need for more water. By necessity, communities often drew raw water from polluted sources. The study concluded that eight million Americans were drinking substandard water. In addition, the study indicated that systems, particularly small ones serving fewer than 500 customers, had problems with source water protection, disinfection, clarification and distribution system pressure. The health effects of these DBPs were unknown at the time and led to concern for the public s safety.