An official website of the United States government.

We've made some changes to EPA.gov. If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Polluted Runoff: Nonpoint Source (NPS) Pollution

National Nonpoint Source Monitoring Program

Our nation's waters are monitored by state, federal, and local agencies, tribes, universities and volunteers.  Water quality data are used to characterize waters, identify trends over time, identify emerging problems, determine whether pollution control programs are working, help direct pollution control efforts to where they are most needed and respond to emergencies such as floods and spills. Nonpoint sources of water pollution are both diffuse in nature and difficult to define.

Water quality monitoring for nonpoint sources of pollution includes the important element of relating the physical, chemical and biological characteristics of receiving waters to land use characteristics.  Without current information, water quality and the effects of land-based activities on water quality cannot be assessed, effective management and remediation programs cannot be implemented, and program success cannot be evaluated.

The purposes of EPA's Section 319 National Nonpoint Source Monitoring Program (NNPSMP) are to:
  • provide credible documentation of the feasibility of controlling nonpoint sources, and
  • improve the technical understanding of nonpoint source pollution and the effectiveness of nonpoint source control technology and approaches.

These objectives are to be achieved through intensive monitoring and evaluation of a subset of watershed projects funded under Section 319.

We are moving many of the publications produced by the NMP to these nonpoint source monitoring pages. In the interim, to see the entire collection of reports, presentations and technical guidance please visit the National Nonpoint Source Monitoring Program  Exithosted by North Carolina State University. 

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.