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Water: Public Water Systems

Definition of a Public Water System

The Environmental Protection Agency (EPA) is publishing guidance to the primacy agencies and EPA's regional offices for their implementation of the Safe Drinking Water Act's (SDWA) 1996 Amendments to the definition of a public water system (PWS) in Section 1401(4). This guidance was developed with information from States, water suppliers, and citizens groups.

  • Defintion of a Public Water System(PWS)in SDWA Section 1401(4)Exit EPA Disclaimer as Amended by the 1996 SDWA Amendments, August 5, 1998 Federal Register notice.
    *Correction: The guidance for the definition of a Public Water System published in the Federal Register on August 5, 1998 (FR Doc. 98-20904) contained an incorrect citation of the SDWA in one of the footnotes.
    **In the Federal Register issue of August 5, 1998, in FR Doc. 98-20904, on page 41941, in the first column, in footnote 3, correct the last sentence to read: See SDWA Section 1401(5).

New Definition: A public water system (PWS) is a system for the provision to the public of water for human consumption through pipes or other constructed conveyances, if such system has at least fifteen service connections or regularly serves at least twenty-five individuals.


Changes to the PWS Definition by the 1996 Amendments
Definition Changes
Constructed Conveyances Expands the means of delivering water to include not only systems which provide water for human consumption through pipes, but also systems which provide water for human consumption through "other constructed conveyances."
Regulation "Constructed conveyance" suppliers newly subject to the PWS Date definition will be regulated as of August 6, 1998.
Exclusions Provides three means by which "constructed conveyance" water systems may be excluded from this definition and two means by which certain piped irrigation districts may be excluded from this definition.

Guidance on Implementing the New PWS Defintion
Guidance
Definitions
  • Human Consumption. Defined to include drinking, bathing, showering, cooking, dishwashing, and maintaining oral hygiene.
  • Constructed Conveyance. Broadly interpreted to refer to any manmade conduit such as ditches, culverts, waterways, flumes, mine drains, or canals.
Determining Constructed Conveyances
  • Natural Waterways. Factors that a primacy agency should consider to determine whether or not a natural waterway is considered a "constructed conveyance" include whether or not it exists in its current configuration substantially from human modifications, who owns or controls the water, and the reason why water is present.
  • Counting. Whether a "constructed conveyance" counts as a connection depends on whether the water supplier knows or should know that the connection exists or that the individuals are using the water from that connection for human consumption.
Water Suppliers' Liability
  • A supplier cannot limit its SDWA liability by not making efforts to gather necessary information and documentation regarding its users' water use, or solely by requiring its users to sign a waiver agreement.
Constructed Conveyance Exclusions
  • Other Than Residential Use Exclusion. A "constructed conveyance" system may automatically exclude a connection from being counted if its use is exclusively for purposes other than residential uses.
  • Alternative Water Exclusion. A "constructed conveyance" system may exclude a connection from being counted if the primacy agency makes a factual determination based on documentation submitted by the water supplier that the water supplier is providing its users at that connection with alternative water that provides the equivalent level of public health protection as the applicable NPDWRs.
  • Treatment Exclusion. A "constructed conveyance" system may exclude a connection from being counted if the primacy agency makes a factual determination based on documentation submitted by the water supplier that the water at the connection is treated to provide the equivalent level of public health protection as the applicable NPDWRs.
Piped Irrigation Exclusion
  • If in existence prior to May 18, 1994, and providing primarily agricultural service with only incidental residential use, a piped irrigation district may not be considered a PWS if all of its connections comply with the alternative water or treatment exclusions (above) for "constructed conveyance" suppliers.

Copies of the final guidance may also be obtained by calling the Safe Drinking Water Hotline at 800-426-4791.  For further information, contact Jon Merkle, Drinking Water Office - (WTR-6), EPA Region 9, 75 Hawthorne Street, San Francisco, California, 94105.

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