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Water: Clean Watersheds Needs Survey

Clean Watersheds Needs Survey Overview


The United States Environmental Protection Agency's Office of Wastewater Management, in partnership with states, territories and the District of Columbia, conducts the Clean Watersheds Needs Survey (CWNS) every four years. The CWNS is conducted in response to Sections 205(a) and 516 of the Clean Water Act. epa watershed poster

This site contains background information, data, reports, and contact information for the CWNS. The highlights are:

The CWNS is a comprehensive assessment of the capital needs to meet the water quality goals set in the Clean Water Act. Every four years, the states and EPA collect information about:

  • Publicly owned wastewater collection and treatment facilities
  • Stormwater and combined sewer overflows (CSOs) control facilities * 
  • Nonpoint source (NPS) pollution control projects* 
  • Decentralized wastewater management

Information collected about these facilities and projects includes:

  • Estimated needs to address water quality or water quality related public health problems
  • Location and contact information for facilities and projects
  • Facility populations served, flow, effluent, and unit process information
  • NPS best management practices

The needs data is organized by the following categories:

 I. Secondary Wastewater Treatment  VII. Nonpoint Source (NPS) Control
 II. Advanced Wastewater Treatment  VII-A. NPS Control: Agriculture (Cropland)
 III-A. Infiltration / Inflow (II) Correction  VII-B. NPS Control: Agriculture (Animals)
 III-B. Sewer Replacement / Rehabilitation  VII-C. NPS Control: Silviculture
 IV-A. New Collector Sewers and Appurtenances  VII-E. NPS Control: Ground Water Protection
 IV-B. New Interceptors Sewer and Appurtenances  VII-F. NPS Control: Marinas
 V. Combined Sewer Overflow (CSO) Correction  VII-G. NPS Control: Resource Extraction
 VI. Stormwater Management Programs  VII-H. NPS Control: Brownfields
 VI-A. Stormwater Conveyance Infrastructure  VII-I. NPS Control: Storage Tanks
 VI-B. Stormwater Treatment Systems  VII-J. NPS Control: Sanitary Landfills
 VI-C. Green Infrastructure  VII-K. NPS Control: Hydromodification
 VI-D. General Stormwater Management  VII-M. NPS Control: Other Estuary Management Activities
 X. Recycled Water Distribtion  XII. Decentralized Wastewater Treatment Systems

This information is used by EPA to document national needs in a Report to Congress. The Report provides Congress, as well as state legislatures, with information to assist their budgeting efforts. The data are also used to:

  • Help measure environmental progress
  • Contribute to academic research * 
  • Provide information to the public * 
  • Help local and state governments implement water quality programs

CWNS data is also summarized and periodically referenced in discussions at the EPA Water Is Worth It facebook page. Exit EPA Disclaimer

If you need assistance to access charts, tables, or graphics found on any CWNS page, contact CWNS staff (cwns@epa.gov).


Contact Us  !  Office of Water

CWNS, U.S. Environmental Protection Agency, Office of Water Management (4204M), 1200 Pennsylvania Avenue, N.W., Washington, D.C.  20460

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