Civil Engineering Reference
In-Depth Information
Early Regulations
From this modest beginning, drinking water standards in the United States began to
develop. As water scientists and engineers developed a more thorough understanding
of treatment technology and the link to waterborne disease, there was also an increased
desire to protect the public from contaminated water. During the early 1900s, the
USPHS developed new regulations that generally kept pace with the advancements in
water treatment science. The first federal drinking water standard for bacteriological
quality was developed in 1914 and applied to only interstate carriers. The Public Health
Service revised and expanded these standards in 1925, and by 1942 the standards had
become the basis for water quality regulations in the United States. The early regu-
lations included bacteriological sampling in the distribution system and maximum per-
missible levels for lead, fluoride, arsenic, and selenium. Chromium was added to the
list in 1946, which completed the early set of mostly nonenforceable guidelines for
the country's 19,000 water suppliers.
1962 Standards
By 1962, the list of mandatory regulations had expanded again, including both
man-
datory
requirements as well as
recommended
requirements. Virtually all 50 states
adopted these standards either as regulations or as guidance, even though they legally
still applied to only interstate carriers.
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The standards set mandatory limits for certain
chemical constituents and recommended concentrations for others, including some ra-
dioactive elements. The bacteriological standards set limits for coliform organisms and
prescribed methods for the collection and laboratory analysis of water samples, in-
cluding the frequency thereof.
The minimum number of water samples per month to be collected for bacteriolog-
ical examination varied according to population served by the system from 2 per month
for 2,000 or fewer people, to 100 per month for 100,000 people, to 300 per month
for 1,000,000 persons. The fact that the total number of bacteriological samples col-
lected and analyzed was often less than the minimum required for significant results
was one of the most common reasons for failure to meet the Drinking Water Standards.
In 1969, the USPHS's Bureau of Water Hygiene surveyed water supply systems
across the country to determine how the well the nation's drinking water compared to
the 1962 standards. This Community Water Supply Study (CWSS) surveyed 969 public
water systems and found that over 40 percent of the systems did not meet the 1962
standards. Table 1-2 summarizes the 1962 mandatory requirements, and Table 1-3
summarizes the 1962 recommended standards.
1974 Safe Drinking Water Act
In the early 1970s, advances in analytical chemistry enabled scientists to begin looking
for contaminants in drinking water in the then unbelievably sensitive ''parts-per-
million'' range. And, in some cases, they didn't like what they saw. While generally
safe from microbial pathogens, some drinking water they examined contained trace
levels of compounds not occurring naturally in water supplies. Some were manmade
chemicals that had either leached or discharged into both groundwater and surface
water sources and were not being removed by conventional treatment methods. A 1972
