The Tampa Bay Seawater Desalination Plant in Apollo Beach is the largest desalination facility in the United States. Operated by Tampa Bay Water, it can produce up to 25 million gallons per day of drinking water, roughly 10 percent of the regional supply during peak operation.
How It Works
The plant draws seawater from Tampa Bay and pushes it through reverse osmosis membranes at high pressure, removing salt and most dissolved solids. The resulting water is then remineralized to adjust pH and blend palatability before entering the distribution system.
When It Runs
The desalination plant is not a constant contributor. It runs most heavily during drought conditions and dry season when reservoir levels drop and groundwater demand from the regional wellfields would otherwise cause land subsidence. During wet season with ample reservoir levels, the plant may run at reduced capacity or for maintenance only.
What It Adds to Your Tap Water
Desalinated water has lower hardness than groundwater but higher sodium content. When blended with wellfield and surface water, the net effect on your tap water is typically a modest reduction in hardness and slight increase in sodium. The blend shifts by season, which is one reason water quality varies throughout the year across the Tampa Bay service area.
The Bottom Line for Homeowners
The desalination plant is a reliable supply backup that improves drought resilience for the entire region. For most homeowners, its primary practical effect is modest seasonal variation in water hardness and taste. A whole-home water conditioning system handles these variations automatically, delivering consistent quality regardless of which sources are feeding the grid that day.