Tampa Bay Water reports near‑full reservoir but warns of below‑average rainfall and possible drought alert

Tampa Bay Water staff told the board on Monday that the agency ended water year 2025 with reservoir storage near full — about 14.65 billion gallons — but that rainfall patterns were uneven through the summer and that September was considerably drier than normal.

Chief Science Officer Warren Hogg said Hurricane Milton’s rainfall early in the water year produced an initial boost to resources, but the region experienced six months of below‑average rainfall afterward. Inland headwaters received substantially less rainfall than coastal areas, making river flows uneven across the service area.

For fiscal year 2025, the agency delivered an average of about 198.47 million gallons per day (MGD) to member governments — slightly below the budgeted 209.7 MGD. The source mix was approximately 55% groundwater, 41% surface water and 4–5% from the seawater desalination facility. Hogg said the desalination plant supplied roughly 2–5% of deliveries in months when it was online.

Hogg warned that because the high rainfall from the prior October will drop out of the 12‑month running average, the region likely will enter a Phase 1 drought alert effective Nov. 1 unless October rainfall is unusually high. Staff said they are preparing public outreach and conservation messaging and coordinating with the Southwest Florida Water Management District.

Board members asked about the desalination plant’s capacity and expansion potential; staff said the renovated facility now has a 20 MGD capacity with room for future expansion and that membranes and systems are functioning well.

The board also heard that the consolidated permit well fields and the South Central Hillsborough well field remain at or below permit limits; staff indicated an increase to the South Central permit is expected at the water management district’s November governing board meeting.