US Water Quality Index
Our composite Water Quality Score combines temperature, reservoir levels, and flow rates to rate conditions for swimming, fishing, and recreation.
How We Calculate Water Quality Score (0–100)
Maximum points when water temp is near ideal 71.5°F (22°C) for most recreational activities.
Full points when reservoir is at or near full pool capacity. Low levels reduce score.
Moderate, stable flow (100–5,000 cfs) earns full points. Extreme highs or lows reduce score.
Lake Champlain At Port Henry Ny
Susquehanna River At Unadilla Ny
Rondout Creek At Rosendale Ny
Canandaigua Outlet At Chapin Ny
Oneida River Near Euclid Ny
Raquette River At Piercefield Ny
Genesee River At Wellsville Ny
Chenango River At Oxford Ny
Seneca River (Erie Canal) Near Port Byron Ny
Chemung River At Chemung Ny
Black River Near Boonville Ny
Neversink River At Neversink Ny
Esopus Creek At Mount Marion Ny
Susquehanna River At Owego Ny
West Canada Creek At Kast Bridge Ny
Onondaga Creek At Spencer Street, Syracuse Ny
Beaver River At Croghan Ny
Mettawee River Near Middle Granville Ny
Canisteo River At West Cameron Ny
Genesee R At Ballantyne Bridge Near Mortimer Ny
Understanding the Water Quality Index
The US Water Quality Index is a composite score designed to give anglers, swimmers, boaters, and outdoor enthusiasts a quick, at-a-glance assessment of water body conditions. Unlike traditional water quality indices that focus on chemical pollutants (which require laboratory analysis), our index uses real-time USGS sensor data to reflect physical conditions relevant to recreation.
Temperature Component (40 points)
Water temperature is the most important factor for recreational fishing, swimming, and wildlife activity. The ideal range for most activities — comfortable for swimming, optimal for bass and walleye fishing — is approximately 65–78°F (18–26°C). Our scoring peaks at 71.5°F and decreases proportionally as temperature moves away from this ideal.
Reservoir Level Component (30 points)
Reservoir levels (measured as a percentage of full pool) reflect drought conditions, drought recovery, flood risk, and overall ecosystem health. A reservoir at full pool (100%) scores maximum points. Severely depleted reservoirs — common during drought — score fewer points. This metric is particularly relevant in western states where water storage is critical.
Flow Rate Component (30 points)
River discharge (measured in cubic feet per second, cfs) indicates safe boating, wading, and kayaking conditions. Moderate, stable flow rates between 100–5,000 cfs are typically ideal for most recreation. Extremely high flows indicate flood risk, while extremely low flows suggest drought stress and limited habitat for fish.