Chemical data from the National Water Quality Monitoring Council (NWQMC) sampled 100 of the largest lakes in the United States from January 1, 2020 to July 15, 2025. Researchers assessed the lake’s cleanliness level.
What they found was Lake Superior was the cleanest and the title of America’s dirtyest lake crossed Lake Okeechobee in Florida.
One cause of the ambiguous appearance of Lake Okeechobee could be high levels of phosphorus estimated at 0.18 mg/L, which stimulates algae growth.
“Overall, America’s largest lakes like Okeechobee are technically a bit murky compared to measurements from last year’s 276 lakes, which are invisible to the human eye,” said David Ciccarelli, CEO of Lake.com.
Each lake was ranked using a score calculated with the following equally assumed factors:
• Dissolved oxygen concentration.
• Ammonia concentration.
•Lead concentration.
•Phosphorus concentration.
•Sulfate concentration.
•Total dissolved solids.
•Turbidity;
• Difference from pH 7.
Lakes were ranked based on total pollution scores, and the higher the pollution score, the more the lake was considered.
Looking at the report, Eric Eikenberg, CEO of the Everglades Foundation, said that continuing funding for the cleaning of Lake Okeechobee is more important than ever.
“Jeb Bush signed the law in 2001 and established a total maximum daily load (TMDL) of phosphorus entering Lake O at 140 metric tons. Over these 20 years, we have not approached the limits of pollution. The lake is no longer a sponge.
this year. Gov. Ron DeSantis has signed a budget that allocates more than $1.4 billion to the Everglades Repair and Water Quality Initiative, President Trump is an active supporter of federal funds for the Everglades Repair, and the 2026 budget request calls for a record high of $446 million in handling the project with the Everglades restoration.
