Within Marathon, Florida, PFAS has been detected in water samples drawn from the public supply — the results are part of the official EPA compliance record for systems here.

Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-05-14

PFAS in Marathon Tap Water

PFAS has been detected in Marathon, Florida drinking water at a maximum level of 0.0503 ppt — below the EPA MCL of 4 ppt (PFOA/PFOS individually).

This analysis covers 80,000 residents across 1 ZIP code in Marathon.

Marathon's overall water quality grade is D (50/100).

Is PFAS in Marathon Water Safe?

If you live in an affected ZIP code, consider installing a reverse osmosis or granular activated carbon filter certified under NSF 53 / NSF 58 and testing your water independently.

PFAS Levels by ZIP Code

Average pfas level across Marathon: 13 ppt

Health Effects of PFAS

• Increased risk of kidney and testicular cancer
• Thyroid disease and immune system suppression
• Reproductive problems and reduced fertility
• Elevated cholesterol and liver effects
• Developmental effects in infants and children

Health risk severity: High. Governed by the PFAS National Primary Drinking Water Regulation (2024).

How PFAS Gets Into Drinking Water

• Firefighting foam (AFFF) used at military bases and airports
• Industrial manufacturing (non-stick coatings, stain-resistant fabrics)
• Wastewater treatment plants that receive industrial discharge
• Landfill leachate from PFAS-containing consumer products

What to Do About PFAS in Marathon Water

1. Install a reverse osmosis system (most effective — removes 90%+ of PFAS)
2. Granular activated carbon (GAC) filters remove some PFAS compounds
3. Look for NSF 53 or NSF 58 certification specifically tested for PFAS
4. Pitcher filters with activated carbon provide partial reduction

Look for filters certified under NSF 53 / NSF 58 for pfas removal.

Related

• PFAS — National Overview
• PFAS in Florida
• Florida Water Quality
• Marathon Water Quality
• Check Your ZIP Code