Safe Drinking Water Act (SDWA)

Drinking water safety cannot be taken for granted. The pubic water system must deal with ongoing threats to the drinking water sources both ground and surface. Threats to the drinking water sources would include pesticides, septic and wastewater systems, chemical disposal, human activities and naturally occurring substances such as arsenic, cadmium, mercury, nitrate, nitrite, lead and other inorganic contaminants.

The Safe Drinking Water Act authorizes EPA to set drinking water standards to protect against both naturally occurring and man-made contaminants that may be found in drinking water. The EPA has established regulations for the primary and secondary drinking water standards.  The primary standards are legally enforceable and public water systems are required to meet these standards. The secondary standards are non-enforceable guidelines for contaminants that are associated with taste, color or odor in the drinking water.  Public Water systems are not required by EPA to meet these secondary standards, but some states require the public water system to comply with these standards.

The National Primary Drinking Water Regulations (NPDWR or primary standards) established standards for chemical, microbiological, radiological, and physical contaminants in drinking water.

The implementation and enforcement of these regulations is the responsibility of the EPA and/or states. States apply to the EPA for the authority to implement the NPDWRs. The authority granted by the EPA to the states for the implementation and enforcement of the NPDWR is called “primacy” — the primary enforcement authority for the drinking water program. The EPA or the states may take enforcement actions against the public water system for failing to meet the established standards.

The EPA has set maximum contaminant levels (MCLs) for the primary drinking water standards.   The MCL is based on short-term or long-term health effects of the contaminant in the drinking water. The MCL is the highest level of a contaminant legally allowed in the drinking water delivered to the customer.

Code of Federal Regulations, Title 40: Protection of the Environment, PART 141—NATIONAL PRIMARY DRINKING WATER REGULATIONS, Subpart A, Section 141.2 defines a maximum contaminant level to mean the maximum permissible level of a contaminant in water which is delivered to any user of a public water system. The original vision of the MCL stated …water which is delivered to the free flowing outlet of the ultimate user of a public water system…. The 1986 amendments removed the words “free flowing outlet.”

Multiple Barrier Approach – There are many aspects to the delivery of safe and fit water to the consumers. They include source water protection, treatment, distribution system integrity, and public information. The public water system is responsible for all aspect of the delivery by ensuring that contaminants in the water do not exceed the standards. Public water systems must use the best possible sources and provide protection programs such as but not limited to the purchasing of watershed land, septic system monitoring, the removal and monitoring of hazardous material. Public water systems in some cases have to treat the water, and optimize the treatment process. Public water systems must test their water frequently for specified contaminants and report the results to states. If a public water system is not meeting these standards, it is the public water system’s responsibility to notify the customers. Public water systems are required to be operated by certified individuals.  To protect drinking water delivered to the customers, the distribution system must meet certain standards of construction. Drinking water that is not properly treated or disinfected, or which travels through an improperly maintained distribution system, may pose a health risk. Providing water that is safe and fit is a major task and requires the public water system to initiate program for all aspects of the delivery of water to the consumers. As part of the distribution system integrity program, the public water system should have an active cross-connection control program. The program should include controlling cross-connections where they exist.  That means having a program for control cross-connections within the domestic pipping system – where individuals are consuming water.  If the public water system is only concerned with protecting the public water distribution system, the consumers are still at risk.

Providing safe drinking water is a partnership that involves EPA, the states, tribes, water systems and their operators and code officials