Keys’ water may look clear, but it’s full of excessive nutrients, contaminants, and pharmaceuticals that are having a harmful impact on our fisheries, our seagrass, our corals – all our marine life. Our health, too, is at risk. A long-standing source of this pollution is the shallow sewage wells still used by the City of Marathon. A group of concerned citizens has initiated a Clean Water Act lawsuit against the City of Marathon, asking the Court to order Marathon to stop using shallow wells and dig a deep well. A win in Marathon can be used to stop shallow well use elsewhere in the Keys. Last Stand supports the lawsuit, and we hope you’ll make your voice heard, too.

Keys Geology Dictates Sewage Solutions

Decades ago, the Keys were mandated by the Courts and the Legislature to move from septic tanks and cesspits to centralized sewer systems, because the wastewater migrated into the surrounding ocean. A good start, but NOT ENOUGH. Why? Because Marathon, the County, and Key West Resort Utilities on Stock Island still use shallow sewage wells. And, for the very same reasons that septic tanks didn’t work, shallow wells don’t work either.

The Keys’ geology of porous limestone, full of conduits and caverns, allows rapid movement of shallow well wastewater into the surrounding coastal waters. Shallow wells only inject the partially treated wastewater about 90-120 feet down into the limestone, where it quickly finds its way to our coastal waters. Fresh water and wastewater are more buoyant than salt water and this, plus the movement of the tides, quickly sends the wastewater into our nearshore waters. Tracer dye tests performed in 2014 at Cudjoe Regional Wastewater Treatment plant, and elsewhere in the Keys, proved this. Citizen pressure and a lawsuit

forced Cudjoe Regional to dig a deep well in 2014. A deep injection well, 3,000 feet deep, is the only way to prevent sewage contamination from reaching nearshore surface waters.

Studies Show Our Waters Aren’t Safe

Data collected for the Florida Keys National Marine Sanctuary (FKNMS) show our protected coastal waters still do not meet state or federal water quality standards and remain impaired.

In February 2022, the Bonefish and Tarpon Trust released a major study of pharmaceutical contamination throughout the entire Keys’ chain high enough to pose a major risk to our fisheries, and the source of that contamination is human wastewater.

A different, recently published study found two plumes of wastewater with extremely high concentrations of sucralose on both the north and south coast of Marathon. Sucralose is an artificial sweetener and is a scientifically accepted indicator of the presence of human wastewater.

Progress in Addressing the Issue

In the 2019 Maui Decision, the US Supreme Court ruled that pollutant discharges through groundwater could be the “functional equivalent of a direct discharge” into U.S. waters, and thus prohibited. Previously, indirect discharges – moving through groundwater in the limestone rock into surface waters – had not been held to be pollution.

Marathon Needs to Switch to Deep Wells

  1. Please write to the members of the Marathon City Council (
  2. Sign the Petition at the FOLKs website (
  3. Share this information – talk to your friendsand create awareness of the problem!

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