Drinking Water Requirements for States and Public Water Systems

Variances and Exemptions

Rule Summary

The Safe Drinking Water Act provides states or EPA the authority to grant variances and exemptions to help public water systems achieve compliance with maximum contaminant levels (MCLs).

Variances allow eligible systems to provide drinking water that does not comply with a National Primary Drinking Water Regulation (NPDWR) on the condition that the system installs a certain technology and the quality of the drinking water is still protective of public health.

There are two types of variances:

  1. General variances are intended for systems that are not able to comply with a NPDWR due to their source water quality and there is no feasible alternate source of water.
  2. Small system variances are for systems serving 3,300 persons or fewer that cannot afford to comply with a NPDWR (but they may be allowed on a case-by-case basis for systems serving up to 10,000 persons). Small system variances are not allowed for microbial contaminants.

Exemptions allow eligible systems additional time to achieve and maintain regulatory compliance with new NPDWRs, while continuing to provide acceptable levels of public health protection. Exemptions do not allow a water system to violate NPDWRs. Rather, they allow additional time to find a compliance solution (i.e., treatment or a new source).

Variance and Exemption Rule Exceptions:

  • Systems that have received a small system variance are not eligible for an exemption.
  • Small System Variances may not be granted for NPDWRs that do not list a small system variance technology (SSTV).
  • Systems that have received an exemption are generally not eligible for a variance.
  • General Variances may generally not be granted for the maximum contaminant level (MCL) for total coliforms or any of the treatment technique (TT) requirements of Subpart H of 40 CFR 141.
  • Small system variances may not be granted for NPDWRs promulgated prior to1986 or MCLs, indicators, and TTs for microbial contaminants.
  • Exemptions from the MCL for total coliforms under Total Coliform Rule and E.coli under the Revised Total Coliform Rule, may generally not be granted.

Variances and Exemptions are not allowed under the Revised Total Coliform Rule.

Variances and Exemptions for Small Drinking Water Systems.

The 1996 Safe Drinking Water Act (SDWA) Amendments revised the existing variances and exemptions regulations [63 FR 157, August 14, 1998]. The revisions incorporate the parts of the SDWA Amendments dealing with

  • Implementing "general" variances for public drinking water systems;
  • Implementing new small system variances for water suppliers that serve fewer than 10,000 people; and
  • Implementing changes related to exemptions.

The revised regulations created a new affordability-based small systems variance. The small system variance may be granted to a public water system serving 3,300 or fewer persons. With the approval of EPA's Administrator, a system serving 3,301-10,000 persons may also be granted a small system variance.

The rule highlights the conditions for granting small system variances under SDWA section 1415(e)(3). This section states that certain affordability criteria must be met in order to qualify for a variance. The affordability criteria set by the state must include assessments that:

  • The small public water system is unable to afford to comply with a NPDWR through treatment;
  • The small public water system is unable to afford to comply by developing an alternative source of water; and
  • The small public water system cannot implement necessary restructuring changes or consolidation with another system. (The State can make a written determination that restructuring or consolidation is not practical in that situation).

If all these conditions are met, the State may grant a small systems variance. The variance states that the system must install, operate, and maintain a nationally listed variance technology. The terms of the variance are set by the State to ensure "adequate protection of human health."

Quick Reference Guide:

Variances and Exemptions: A Quick Reference Guide (PDF)(4 pp, 112 K About PDF) The quick reference guide provides a summary of the Variances and Exemptions Rule.

Rule History

The Safe Drinking Water Act (SDWA) defines and describes conditions for granting variances and exemptions in SDWA sections 1415 and 1416. As a result of the 1996 SDWA amendments the existing language regarding variances and exemptions was revised.

The rule revision included procedures and conditions under which a State, Tribe, or the EPA Administrator may issue small system variances to public water systems serving less than 10,000 persons. This rule-making was intended to provide regulatory relief to all public water systems, particularly small systems.

Federal Register Notices

Public Input - Historical Documents


General variances, small system variances and exemptions are granted to water systems only under special conditions. When treated water cannot meet the MCL, there are no PWS restructuring options, there are no other sources of water, and no affordable technology the state may grant a small system a variance.

An exemption may only be granted if the system agrees to undergo capital improvements that may take an extended amount of time to be completed so that the treated water will meet the MCL.

There is a significant public notice and public outreach component for a PWS operating under a variance or exemption. Below are some guidance documents to help implement variances and exemptions.

Small Drinking Water Systems Variances – summarizes regulations issued in 1998 that codify provisions of the Safe Drinking Water Act, as amended in 1996, dealing with “general” variances available to all sizes of public water systems; implement new small system variances for water suppliers that serve fewer than 10,000 people; and implement changes related to exemptions.

Variance and Exemption Memos

The following Water Supply Guidance Memos relating to the Variances and Exemptions Rule are available on the EPA website at http://water.epa.gov/lawsregs/guidance/sdwa/wsg.cfm

  • Variances and Exemptions from Maximum Contaminant Levels under the Safe Drinking Water Act (WSG 17) May 21, 1979
    This memo discusses the differences between variances and exemptions in not being able to meet the MCL. It was written before the 1996 SDWA amendments so it does not take into account the small system variance.
  • Illegal Use of Variance/Declaratory Judgment (WSG 18) 07/21/1979; Revised 11/1998
    This memo is the introduction to WSG 18A describing
  • Methods of Preventing States from Using Illegal Variances (WSG 18A) 08/10/1979
    This memo is the attachment to WSG 18. It outlines some enforcement actions available if.
  • Variances and Exemptions for Fluoride Revised in the Phase II Rule* (WSG H49) 07/1992
    This memo outlines EPA's inclusion of the use of bottled water, point of use devices, and point of entry devices for granting a variance from the MCL for fluoride.
  • Variances and Administrative Orders (WSG H22) 08/1989; Revised 09/1998
    This memo replies to the question: May a State issue a variance after the system has applied the best available technology and still cannot meet the MCL?