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.
Frog Creek Near Rubonia Fl
South Canal Near Vero Beach, Fl
West Lake Outlet To Long Lake Near Flamingo, Fl
Withlacoochee River Near Inverness, Fl
East Lake Outfall At E. Chelsea St. Near Tampa Fl
Lateral 101 At S-101, Near Lake Buena Vista, Fl
Sweetwater Creek Near Sulphur Springs Fl
Peace River At Clear Springs Near Bartow Fl
Reedy Creek Below S-40, Near Loughman, Fl
Carter Creek Near Sebring Fl
Anclote River Near Odessa Fl
Big Slough At Tropicaire Blvd Near North Port Fl
Withlacoochee River At Rital Fl
Levee 31 North Extension At 4 Mile Nr West Miami F
Lt Econlockhatchee R At State Hwy434 Nr Oviedo, Fl
Suwannee River At White Springs, Fla.
Baker Creek At Mcintosh Road Near Antioch Fl
Gator Slough West Of Us-41 Near Ft. Myers Fl
Payne Creek Near Bowling Green Fl
Lake Tarpon Canal At S-551, Near Oldsmar 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.