Florida's springs, rivers, and coastlines are under assault from nutrient pollution, agricultural runoff, and aging infrastructure. Water that was once gin-clear is turning green.
The State of Florida's Water
1,000+Waterbodies on Florida's impaired waters list
67%Springs with elevated nitrate levels
$2.2BAnnual tourism revenue at risk from algal blooms
150+Days of toxic algae advisories in 2018
Florida's Department of Environmental Protection (DEP) maintains an official list of impaired waterbodies — water bodies that fail to meet state water quality standards. As of 2024, over 1,000 waterbodies are on that list, and the number is growing. The primary culprits are excess nitrogen and phosphorus from agriculture, septic systems, stormwater runoff, and wastewater treatment plants.
Nitrogen Sources in Florida's Waterways
Agriculture
42%
Septic Systems
14%
Urban Stormwater
22%
Wastewater Plants
12%
Atmospheric
10%
Estimated statewide nitrogen loading contributions — varies by watershed
Spring Nitrate Levels vs. Ecological Threshold
Natural Background
0.05
Algae Threshold
0.35
Many Springs Today
1.0+ mg/L
Nitrate levels in mg/L — many springs now exceed 20x natural background
Seagrass Coverage Change by Region
Indian River Lagoon
−58%
Tampa Bay
+40% ✓
FL Statewide Avg
−30-50%
Tampa Bay shows recovery is possible with aggressive nutrient reduction
Key Water Quality Issues
Harmful Algal Blooms (HABs)
When excess nutrients — particularly nitrogen and phosphorus — enter warm, slow-moving water, they fuel explosive growth of cyanobacteria (blue-green algae). These blooms can produce microcystin and other toxins that are dangerous to humans, pets, and wildlife.
Red Tide (Karenia brevis): A naturally occurring marine algal bloom amplified by nutrient runoff. It kills fish, sea turtles, manatees, and dolphins. The 2017–2019 bloom killed an estimated 2,000+ tons of marine life on the Gulf Coast.
Blue-Green Algae: Freshwater cyanobacteria blooms have become annual events on Lake Okeechobee, the St. Lucie Estuary, and the Caloosahatchee River. Blooms can produce toxins 10x more powerful than cyanide.
Health effects: Skin rashes, respiratory irritation, gastrointestinal illness. Long-term microcystin exposure is linked to liver damage. Pets that drink bloom-contaminated water can die within hours.
⚠️ Safety: Never swim in, fish from, or let pets drink water with visible algal blooms. Check Florida's Algal Bloom Dashboard before heading out.
Lake Okeechobee & Estuary Discharges
Lake Okeechobee sits at the heart of Florida's water crisis. The lake receives nutrient-laden agricultural runoff from the north, and when water levels rise dangerously for the aging Herbert Hoover Dike, the Army Corps of Engineers releases polluted water east to the St. Lucie Estuary and west to the Caloosahatchee River.
Nutrient loading: The lake receives ~500 tons of phosphorus annually — far exceeding the 105-ton Target TMDL set by DEP
Discharge impacts: Freshwater discharges devastate the naturally brackish estuaries, killing oyster reefs, seagrass beds, and driving away fish
Everglades starvation: Water that should flow south to the Everglades is instead diverted east and west, depriving the River of Grass of its lifeblood
EAA Reservoir: The $4 billion Everglades Agricultural Area storage reservoir, approved in 2020, aims to reduce harmful discharges by storing and cleaning water south of the lake. Expected completion: 2029.
Spring Clarity Decline
Florida's 700+ springs were once famous for crystalline water with 100+ foot visibility. Today, many iconic springs are clouded by algae growth fueled by excess nitrates — primarily from septic tanks and fertilizer runoff percolating through Florida's porous limestone aquifer.
Nitrate levels: Background nitrate in Florida groundwater is ~0.05 mg/L. Many springs now exceed 1.0 mg/L — 20x the natural level. The ecological threshold for algal growth is ~0.35 mg/L.
Affected springs: Silver Springs, Rainbow Springs, Ichetucknee Springs, Wakulla Springs, and dozens of others show declining clarity and increased algal coverage
Septic contribution: An estimated 2.7 million septic systems in Florida contribute ~14% of total nitrogen loading to groundwater
Recovery time: Because groundwater moves slowly through the aquifer, even if nutrient inputs stopped today, springs wouldn't recover for decades
Seagrass Loss
Seagrass beds are nursery habitat for fish, foraging grounds for manatees and sea turtles, and natural carbon sinks. Florida has lost an estimated 30–50% of its seagrass coverage since the 1950s.
Indian River Lagoon: Lost over 58% of seagrass coverage from 2011–2021, contributing to unprecedented manatee die-offs (1,100+ deaths in 2021 alone from starvation)
Tampa Bay: A rare success story — aggressive nitrogen reduction since the 1990s has restored seagrass to 1950s levels. Proof that water quality improvements work.
Mechanism: Excess nutrients fuel algal blooms and epiphytic algae that shade out seagrass, which requires clear, sunlit water