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.
Horse Creek Near Myakka Head Fl
Popash Slough Near Okeechobee, Fl
Pithlachascotee R Bl Suncoast Pkwy Nr Fivay Jct Fl
Tamiami Canal At S-12-B Nr Miami, Fl
South Prong St Sebastian River Near Sebastian,Fl
Elevenmile Creek Nr West Pensacola, Fl
Jumper Creek Canal Near Bushnell, Fl
South Lake Outlet At S-15, Near Vineland, Fl
Howell Creek At State Hwy 434 Near Oviedo, Fl
L-67C Canal Dns Of S-633 Flowway Nr Coopertown,Fl
Saddle Creek At State Hwy 570 Near Eaton Park Fl
Econfina River Near Perry, Fla.
L-28 Interceptor Canal Blw S-190 Near Clewiston Fl
St Joe Creek At 62Nd St Nr Pinellas Park Fl
Shell Creek At Circle K Groves Near Ft Ogden Fl
Wolff Creek Nr Okeechobee,Fl
Frog Creek At Buffalo Road Near Rubonia Fl
Main Canal At Vero Beach, Fl
Jane Green Creek Near Deer Park, Fl
Cuthbert Lake Outlet Near Flamingo, Fl
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.