WaterQualityWatch -- Continuous Real-Time Water Quality of Surface Water in the United States

USGS is updating how statistical information is delivered. WaterWatch and WaterQualityWatch will be retired around February 24, 2026. Explore alternative tools and share feedback at wdfn@usgs.gov.

Real-Time Chlorophyll, in µg/l

Map of , showing which states provide real-time computed water-quality data
Explanation

* Site operated on a seasonal basis or currently is not operating.
No values are available for the last 6 hours.

The "Real-time" map tracks short-term changes (over several hours) of water quality. Although the general appearance of the map changes very little from one hour to the next, individual sites may change rapidly in response to major rain events or to reservoir releases. The data used to produce this map are provisional.