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Agenda Item: |
Prepared By: Jeffrey E. Poteet |
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Business: Presentation |
Department: Water and Sewer |
Subject:
Title
Presentation - Meeting Marco Island’s Future Water Demands - Jeffrey E. Poteet, General Manager, Water & Sewer Department
Body
BACKGROUND:
In September 2025, the Water and Sewer Department presented the City's 2024 Water Capacity Analysis Report (CAR) to City Council. The CAR evaluated the ability of the City's potable water system to meet existing and projected demands through 2040. The analysis identified adequate storage and distribution capacity but highlighted constraints associated with water treatment capacity, source-water availability, increasing potable water demands, and the need for future improvements at both the North Water Treatment Plant (NWTP) and South Water Treatment Plant (SWTP).
The City's potable water system is supplied by two treatment facilities. The NWTP utilizes surface water from Marco Lakes (located approximately 9-miles north of Marco Island), supplemented by Aquifer Storage and Recovery (ASR), and is currently permitted to produce 6.67 million gallons per day (MGD). The SWTP utilizes brackish groundwater from the Mid-Hawthorn Aquifer and is permitted to produce 6.0 MGD, providing a combined permitted treatment capacity of 12.67 MGD.
However, permitted treatment capacity does not represent the amount of water the City can reliably produce on an annual basis. While the SWTP has 6.0 MGD of permitted treatment capacity, its current water use permit limits annual average production to approximately 2.7 MGD. Combined with the NWTP's current permitted capacity, available source water limits annual average production to approximately 9.4 MGD. Increasing the NWTP's treatment capacity and obtaining additional water allocations for the SWTP are therefore important components of the City's long-term water supply strategy.
Potable water demand has continued to increase. Between 2015 and 2025, average daily demand increased from 7.39 MGD to 10.35 MGD. In 2025, daily demand exceeded 12 MGD on 32 days. Through July 2026, demand exceeded 12 MGD on an additional 24 days. Long-term projections indicate that by buildout in approximately 2040, average daily demand is expected to reach 10.41 MGD, maximum-month average daily demand approximately 11.86 MGD, and maximum-day demand approximately 13.67 MGD.
Since the September 2025 presentation, the City has continued implementing improvements to address these capacity and reliability concerns. An application has been submitted to the Florida Department of Environmental Protection to re-rate the NWTP from 6.67 MGD to 8.5 MGD, allowing the City to make greater use of available source water. The City has also replaced membrane elements at both treatment plants, is commissioning new biological treatment facilities at the Source Water Facility, is completing high-service pumping improvements, and is advancing raw-water pipeline and wellfield improvements.
At the same time, the City must prepare for longer-term infrastructure and regulatory needs. These include rehabilitation and modernization of aging treatment facilities, improvements to SWTP wellfield performance and reverse-osmosis recovery, potential modifications to the NWTP treatment process, and improvements necessary to comply with emerging PFAS drinking-water standards.
This presentation will update City Council on potable water demand trends, available treatment and source-water capacity, progress on recent and ongoing improvements, regulatory considerations, and the City's proposed schedule for future water treatment and water supply improvements. The objective is to ensure that future investments are appropriately timed to maintain adequate capacity, redundancy, water quality, and reliability as the City's potable water demands continue to increase.
FUNDING SOURCE / FISCAL IMPACT: N / A
RECOMMENDATION: N/A
POTENTIAL MOTION: N/A