EPA works with state, local and tribal authorities to carry out nationwide water monitoring projects. Monitoring includes the physical and chemical measurement of the levels of dissolved oxygen, suspended sediments, nutrients, metals, oils, and pesticides in water. It also includes assessments of temperature, flow, water color, the conditions of stream banks and lake shores and the examination of aquatic wildlife. Increasingly, the EPA's monitoring efforts are focused on a holistic approach which examines the interaction of all media within a single watershed. This approach allows for the identification of changes in water quality, the discovery of emerging water quality problems, the assessment of pollution control measures, the effectiveness of compliance, and how to respond in an emergency response. Water monitoring information is made available to the public through resources such as the STORET database.

Recommended EPA Web pages

• Laboratories and Monitoring
  EPA's drinking water standards program has established health based standards for more than 80 contaminants.
• Monitoring and Assessing Water Quality
  Methods and tools to monitor, assess, and report on the health of America's water resources.
• Beaches
  Information on beach protection, water quality, and beach reports and references.