Major sections of the CWA that depend upon monitoring and assessment of water quality:

• Section 305(b)
  • States/Tribes must report on the condition of all waters in their jurisdiction. (Specifically the extent to which the waters support healthy aquatic life and recreation in and on the water.)
  • EPA must summarize these reports in a “Report to Congress” every 2 years
• Section 303(d)
• • States/Tribes must submit a prioritized list of waters that do not meet water quality standards and need total maximum daily loads (TMDLs).
• Other CWA programs
  • States/Tribes must establish and periodically refine water quality standards.
    • Monitoring data are very important for setting water quality standards for such pollutants as excess nutrients and sediments because their impacts vary depending upon their ecological setting.
  • States/Tribes must issue and ensure compliance with National Pollutant Discharge Elimination System (NPDES) permits.
  • States/Tribes should manage nonpoint sources to meet their water quality standards.
  • EPA and the States/Tribes should have monitoring data to help them address new challenges such as climate change, energy production, emerging contaminants, and natural and man-made disasters.

Return to Supplemental Module: Monitoring and Assessment