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Water: Public Water Systems

Small Drinking Water Systems Variances

Recent Events

Stakeholder Meeting

On May 20, 2009, EPA held a public meeting to discuss policies to assure the equitable treatment of small drinking water system customers.  These policies include small drinking water system variance policies, the Drinking Water State Revolving Fund (DWSRF), capacity development, and operator training programs.  The public meeting provided a forum for public discussion on how these policies could be improved to better provide equitable treatment of small system customers.


Federal Register Notice of Meeting


The 1996 amendments of the Safe Drinking Water Act (SDWA) provide States the authority to grant variances to small public water systems that cannot afford to comply with a primary drinking water standard. These variances allow a system to install and maintain technology that can remove a contaminant to the maximum extent that is affordable and protective of public health in lieu of technology that can achieve compliance with the regulation. One of the conditions for States to grant variances on a case-by-case basis is that the EPA must have found for systems of a similar size and with similar source water that there are no affordable technologies available that achieve compliance with the standard, but that there are affordable variance technologies that are protective of public health. 

EPA currently determines if there are affordable compliance technologies available to small systems by comparing (for a representative system) the current household cost of water plus the estimated additional cost to comply with a new rule to an affordability ‘‘threshold’’ of 2.5 percent of the median household income (MHI).

In 2006, EPA published a Federal Register notice to request comment on revisions to EPA’s national affordability methodology for small drinking water systems and a methodology for determining if an affordable variance technology is protective of public health.  The proposal described a number of options for revising the affordability methodology for public review and comment.

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Frequently Asked Questions

What is a small system variance?
A small system variance enables a system to utilize a treatment technology that achieves the maximum removal of the contaminant that is both affordable and protective of public health, but does not remove the contaminant to the degree specified by the drinking water regulation. States may grant small system variances only for those drinking water standards that EPA has determined are unaffordable for one or more categories of systems.

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How does EPA currently determine if variances should be made available for states to grant to small systems?

The Safe Drinking Water Act (SDWA) requires EPA to identify affordable compliance treatment technologies for small systems for each new drinking water standard. EPA must evaluate treatment technologies and their costs for three categories of small systems; systems serving 25 to 500 people, systems serving 501 to 3,300 people and systems serving 3,301 to 10,000 people. If EPA cannot identify affordable compliance technologies for some or all of the systems in these categories, EPA must identify variance treatment technologies that achieve the maximum reduction affordable, and determine if the variance technologies are protective of public health.

EPA currently determines if compliance with a drinking water standard is affordable by comparing the current cost of water plus the estimated additional treatment cost of the new standard to an affordability threshold of about $1000 (this threshold is calculated by taking 2.5% of the median income among small systems).

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Why is EPA re-examining the current methodology?

As part of the 2002 appropriations process, Congress directed EPA to review the methodology by which it evaluates the affordability of drinking water standards for small systems. In response, EPA sought the advice of Science Advisory Board (SAB) and National Drinking Water Advisory Council (NDWAC). The SAB and NDWAC both recommended that EPA consider modifications to its current methodology.

In the 2010 Budget, EPA committed to work with State and local governments to address Federal drinking water policy in order to provide equitable consideration of small system customers.  EPA is reevaluating a number of measures including the small system variance policy, its existing variance determination methodology, and other strategies, such as small water system capacity development and the Drinking Water SRF program.  EPA is committed to providing safe and affordable drinking water to all customers in all drinking water system size categories.

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What did the Science Advisory Board and National Drinking Water Advisory Council recommend?

The SAB and NDWAC made a number of recommendations regarding the method by which EPA evaluates the affordability of compliance with drinking water standards. Some key recommendations made by both the SAB and the NDWAC include: (1) EPA should consider the household cost of each new regulation on an incremental basis rather than a total cost of all water treatment regulations, and (2) EPA should consider reducing the current affordability threshold.

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Will a revised small drinking water system variance policy impose any requirements on public water systems?

Neither the national affordability methodology nor the methodology for determining if an affordable variance technology is protective of public health imposes any requirement on any person or entity. Rather, these methodologies will be applied by EPA in evaluating small system affordability of future drinking water standards except for regulations that address microbial contaminants (including bacteria, viruses, or other organisms) or indicators for microbial contaminants. The law does not allow small system variances for microbial contaminants SDWA section (1415(e)(6)(B)).

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Additional Information on Variances and Exemptions

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Additional Information and Resources to Assist Small Systems

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