Waterworks, water distribution systems, sewerage, and sewage treatment works are an integrated system.
The primary purpose of this system is to protect the public health and to prevent nuisances. This is
achieved as follows:
• Waterworks produce potable waters that are free of pathogens and poisons.
• Water distribution systems prevent the posttreatment contamination of potable water while storing
it and delivering it to users upon demand.
• Sewerage systems efficiently and safely collect contaminated used water, thereby preventing disease
transmission and nuisance, and transmit it to sewage treatment works without loss or contamination
of the surrounding environment.
• Sewage treatment works remove contaminants from the used water prior to its return to its source,
thereby preventing contamination of the source and nuisance.
Overall, this system has been successful in controlling waterborne disease, and such disease is now rare
in modern industrial economies.
The secondary purpose of sewage treatment is to preserve wildlife and to maintain an ambient water
quality sufficient to permit recreational, industrial, and agricultural uses.
Potable water quality in the U.S. is regulated by the U.S. EPA under authority of the “Safe Drinking Water
Act” of 1974 (PL 93–523) and its amendments. The Act applies to any piped water supply that has at
least 15 connections or that regularly serves at least 25 people. The U.S. EPA delegates day-to-day
administration of the Act to the states. The fundamental obligations of the U.S. EPA are to establish
primary regulations for the protection of the public health; establish secondary regulations relating to
taste, odor, color, and appearance of drinking water; protect underground drinking water supplies; and
assist the states via technical assistance, personnel training, and money grants. Regulations include criteria
for water composition, treatment technologies, system management, and statistical and chemical analytical
Violations of Drinking Water Regulations
Water supply systems must notify the people they serve whenever:
• A violation of a National Primary Drinking Water Regulation or monitoring requirement occurs
• Variances or exemptions are in effect
• Noncompliance with any schedule associated with a variance or exemption occurs
If the violation involves an MCL, a prescribed treatment technique or a variance/exemption schedule,
a notice must be published in the local newspapers within 14 days. If there are no local newspapers, the
notice must be given by hand delivery or posting. In any case, notification by mail or hand delivery must
occur within 45 days, and notification must be repeated quarterly as long as the problem persists.
Notification must be made by television and radio within 72 h if any of the following occur: (1) the
violation incurs a severe risk to human health as specified by a state agency, (2) the MCL for nitrate is
violated, (3) the MCL for total coliform when fecal coliform or
THE CIVIL ENGINEERING HANDBOOK SECOND EDITION
J.y. Richard Liew