Ambient Water Quality Tools

The Ambient Water Quality tools track water quality data and their impacts to the environment and human health.


ATTAINS provides information on the conditions of surface waters as reported by the states. Water quality assessment and Total Maximum Daily Loads (TMDL) information are required every two years under Clean Water Act Sections 305(b) and 303(d). Read more about ATTAINS.


Beach Advisory and Closing Online Notification (BEACON) is a system that provides to the public a database of pollution occurrences for coastal recreation waters. It contains state-reported beach monitoring and notification data and is available online. Read more about BEACON 2.0.

National Listing of Fish Advisories (NLFA) Technical Maps

NLFA Technical Maps provides interactive mapping and search tools for viewing fish advisories and fish tissue sampling data. Read more about NLFA Technical Maps.


NPDAT Web-based tool helps states develop effective strategies for reducing nitrogen and phosphorus pollution. The tool consists of a geospatial viewer and data download tables. Read more about NPDAT.

National Stormwater Calculator

National Stormwater Calculator estimates the annual amount of rainwater and frequency of runoff from a specific site based on local soil conditions, land cover, and historic rainfall records. Read more about National Stormwater Calculator.

Rainfall Erosivity Factor Calculator

The Rainfall Erosivity Factor Calculator determines if small construction projects can obtain a waiver from NPDES stormwater permitting. Read more about Rainfall Erosivity Factor Calculator.


STORET is a repository that EPA, government agencies, universities, and citizens useĀ for water quality, biological, and physical data. Read more about STORET.

Water Quality Exchange (WQX)

The WQX framework assists states, tribes, and others to submit and share water quality monitoring data. Read more about WQX.