5601 Overseas Highway, Marathon, FL · Monroe County · Publicly Owned Treatment Works
City Of Marathon Area 4 WWTP is a publicly owned wastewater treatment works in Marathon, Monroe County, Florida treating an average of 0.4 million gallons per day against a permitted design capacity of 0.4 MGD. It discharges under NPDES permit FLA550973 (effective), which expires in September 2030.
4 treatment structures and unit processes identified at City Of Marathon Area 4 WWTP.
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See the full treatment train at City Of Marathon Area 4 WWTP: structures, unit processes and planned upgrades, with exact unit counts.
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
1 verified contact for City Of Marathon Area 4 WWTP, with validated emails and direct phone numbers.
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Names, validated emails and direct phone numbers for decision-makers at City Of Marathon Area 4 WWTP, plus the full compliance history and discharge data.
Marathon · 1 mi away
0.25 MGD
Marathon · 2 mi away
0.45 MGD
Marathon · 4 mi away
0.2 MGD
Marathon · 9 mi away
0.2 MGD
Duck Key · 11 mi away
0.27 MGD
Big Pine Key · 13 mi away
0.02 MGD
Layton · 17 mi away
0.07 MGD
Cudjoe Key · 28 mi away
0.94 MGD
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed October 26, 2026; facility record last updated October 22, 2026.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Tertiary treatment · Significant industrial user · all terms