EPA divides water pollution sources into two categories: point and non-point. Point sources of water pollution are stationary locations such as sewage treatment plants, factories and ships. Non-point sources are more diffuse and include agricultural runoff, mining activities and paved roads. Under the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating point sources that discharge pollutants into waters of the United States. EPA works with state and local authorities to monitor pollution levels in the nations water and provide status and trend information on a representative variety of ecosystems.

Recommended EPA Web pages

• Summary of the Clean Water Act
  The Clean Water Act establishes the basic structure for regulating discharges of pollutants into the waters of the US and regulating quality standards for surface waters.
• What is Nonpoint Source (NPS) Pollution? Questions and Answers
  Questions and answers about nonpoint source pollution.
• National Pollutant Discharge Elimination System (NPDES)
  The National Pollutant Discharge Elimination System permit program controls water pollution by regulating point sources that discharge pollutants into waters of the United States.

Drinking Water
Drinking Water System, Protection

Ground Water
Discharge, Hydrogeology, Protection, Runoff, Wells

Storm Water
Combined Sewer Overflows (CSOs), Industrial Storm Water, Permits, Sanitary Sewer Overflows (SSOs), Wet Weather Programs

Surface Water
Dumping, Marine Debris

Wastewater
Animal Feeding Operations (AFOs), Biosolids, Discharges, Effluent Guidelines, Effluents, Industrial Wastewater, Municipal Wastewater Treatment, National Pollutant Discharge Elimination System (NPDES), Permits, Publicly Owned Treatment Works (POTWs), Standards, Treatment, Wastewater Systems

Water Infrastructure

Water Pollution
Community Involvement, Cost Benefit Analysis, Data, Nonpoint Sources, Point Sources, Reporting, Testing, Transboundary Pollution

Water Pollution Control
Pretreatment, Remediation, Trading, Wastewater Treatment

Water Pollution Effects
Economic Effects, Environmental Effects, Health Effects

Water Pollution Legal Aspects
Compliance, Enforcement, Guidance, Legislation, Permits, Public Comment, Regulations, Standards, Total Maximum Daily Loads (TMDLs)

Water Quality Monitoring
Bioassessment, Criteria, Health Advisories, Models, Standards