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Water: Water Quality Standards Academy

Basic Course: Supplemental Topics - Health Introduction

Introduction: EPA Role in Developing Human Health Criteria

Human Health Ambient Water Quality Criteria

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Section 304(a)(1) of the Clean Water Act (CWA) requires that EPA periodically review and publish criteria for water quality that accurately reflect the latest scientific knowledge on the kind and extent of all identifiable effects on human health and welfare. These criteria are not Federal regulations. However, they are sometimes used by States and Tribes to establish standards.

That is, the criteria published by EPA present scientific data and guidance on the effects of pollutants that can be used to derive regulatory requirements, including the promulgation of:

  • Water quality-based effluent standards (CWA, Section 302).
  • Water quality standards (CWA, Section 303).
  • Toxic pollutant effluent standards (CWA, Section 307).

Key Point. EPA’s national recommended water quality criteria provide guidance to States and Tribes in adopting water quality standards in support of the CWA. They also provide guidance to EPA when the Agency promulgates Federal regulations under the CWA.

In 2000, EPA updated its guidance for deriving human health water quality criteria. The updated methodology incorporates significant scientific advances made in recent decades, particularly in the areas of cancer and noncancer risk assessments, exposure assessments, and methodologies to estimate bioaccumulation in fish. The information in this module is based on the updated methodology (see Resource item below). 

Resource. EPA Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health (October 2000).

In addition to the methodology document, there are two technical support documents that accompany the methodology. One covers the toxicology components of the methodology and the other the bioaccumulation components. Two additional technical support documents on exposure assessment and development of site-specific bioaccumulation factors are presently being developed and will be posted to the web when they are completed. The two final technical support documents—as well as a draft of the site-specific BAFs document (June 2008)—can be accessed from the Resource item above.


Resource. The most recent human health criteria developed by EPA are available on the Agency’s website as part of its compilation of national recommended water quality criteria.


Resource. More generally, see also EPA’s web page on Human Health Criteria. This page includes information about additional human health criteria that are under development by EPA. 

For informational purposes only–Not official statements of EPA policy.

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