Clearest Lake in Florida: Top 25 by Secchi Depth

Jackson-Silver Lake is the clearest lake in Florida by Secchi depth, with water transparency of 25 feet. Secchi depth is measured by lowering a black-and-white disk until it disappears from view — deeper readings mean clearer water. Located in Jackson County, Jackson-Silver Lake has a water quality grade of B (Good).

Water clarity is measured by Secchi depth, named after the 19th-century Italian astronomer Pietro Angelo Secchi who developed the method. A standardized black-and-white disk is lowered into the water on a rope; the depth (in feet or meters) at which the disk disappears from view is recorded. Greater Secchi depth means clearer water — usually a sign of low sediment, low phosphorus, and limited algae growth.

Lake clarity is driven by three factors: low suspended sediment (clay, silt), low nutrient load (especially phosphorus, which fuels algae), and low chlorophyll-a (active algae biomass). Deep glacial lakes with rocky basins and forested watersheds — common in northern Florida — tend to be clearest because they have little soil runoff and limited nutrient input. Shallow agricultural-watershed lakes are typically less clear because they receive more sediment and fertilizer runoff.

Not always. Clarity (Secchi depth) is measured and shown; the letter grades nutrients and algae — total phosphorus and chlorophyll-a — against that lake’s EPA ecoregion classes. A lake can be very clear but still have elevated phosphorus that just hasn't bloomed yet. See our companion cleanest-lakes ranking for Florida for the nutrient-and-algae list.

Florida's clearest waters compete with the most pristine lakes in our 38-state dataset, where top-tier lakes typically register Secchi depths of 15–25 feet. Nationally, the gold standard is Crater Lake in Oregon (~100 ft) and Lake Tahoe (~65 ft).