Tampa Bay and Hillsborough River Water Quality

The Environmental Protection Commission of Hillsborough County collects the core Tampa Bay record, sampling the bay every month since 1974 at 45 fixed stations, according to the Tampa Bay Estuary Program (TBEP, Water Quality Report Card).

The stations run from the low-salinity upper reaches of Tampa Bay down to the mouth, where the bay meets the Gulf, and samples are taken by water collection or monitoring sonde at the bottom, middle or surface depending on what is being measured (TBEP). The estuary program says tracking Tampa Bay's change from the past to the present would not have been possible without that long-term record.

The commission describes its full program as larger: over 250 surface water stations across Tampa Bay, the rivers and their tributaries, and Lake Thonotosassa (EPC Water Division). The two counts describe different scopes: the estuary program's 45 are the fixed Tampa Bay stations behind its report card, while the commission's figure also takes in the rivers, their tributaries and Lake Thonotosassa.

EPC staff also help collect data for the annual Tampa Bay seagrass survey. The Water Division is at 3629 Queen Palm Dr. in Tampa, phone 813-627-2600 (EPC). Last verified: October 18, 2026, against the Environmental Protection Commission of Hillsborough County, the Tampa Bay Estuary Program, the Florida Department of Environmental Protection and the Southwest Florida Water Management District websites.

The Tampa Bay Estuary Program turns the commission data into an annual report card that gives each of four segments, Old Tampa Bay, Hillsborough Bay, Middle Tampa Bay and Lower Tampa Bay, one of three management actions (TBEP, Water Quality Report Card).

The ratings serve both the estuary program and the Tampa Bay Nitrogen Management Consortium, and the program posts a two-page summary, an interactive dashboard and a provisional report card (TBEP). The 2025 report card itself is posted as a summary document and dashboard rather than as text on the page, so segment-by-segment 2025 ratings are not restated here.

The long view on the same page is steady. The estuary program says nutrient reductions by the late 1970s, led by wastewater treatment improvements in 1979, were followed in the 1980s by clearer water and lower chlorophyll across Tampa Bay, and that conditions have generally held since (TBEP).

Nitrogen in Tampa Bay is managed under the Tampa Bay Estuary Reasonable Assurance Plan, developed by the estuary program and members of the Tampa Bay Nitrogen Management Consortium in cooperation with the EPA, FDEP and other regional stakeholders (FDEP, Tampa Bay Estuary RAP).

The plan also supports site-specific chlorophyll-a thresholds for each Tampa Bay segment, set at levels beyond which FDEP says an imbalance of flora and fauna may occur (FDEP). In May 2008 the department agreed that the plan would satisfy the nutrient standards if allocations were developed for every nitrogen source to the bay, and in December 2010 the DEP secretary adopted the 2009 addendum, an allocation and assessment report.

The consortium itself was formed in 1996 by local governments and private industries to hold the line on nutrient pollution for the sake of Tampa Bay seagrass, and its resource list includes the 1998 EPA federal TMDL and annual compliance assessments for 2022 through 2025 in the 2022 to 2026 period (TBEP, Nitrogen Management Consortium). The FDEP plan page was last modified Dec. 13, 2024, and the newest update it lists is from 2022.

Old Tampa Bay has its own working group because it periodically fails to attain its chlorophyll-a threshold, according to the Tampa Bay Nitrogen Management Consortium (TBEP, Nitrogen Management Consortium).

The Old Tampa Bay Working Group is made up of consortium participants with an interest in proactively addressing that periodic non-attainment. Its meeting record on the consortium page includes a technical memo on relationships between total nitrogen and chlorophyll-a in Old Tampa Bay, an assimilative capacity assessment and Pyrodinium monitoring (TBEP).

The consortium page lists the next Old Tampa Bay Working Group meeting for October 29, 2026, after sessions on August 31 and May 29, 2026, and the August 31 agenda included an Old Tampa Bay Stormwater Controls Project update (Nitrogen Management Consortium).

The Florida Department of Environmental Protection lists bacteria basin management action plans for the Hillsborough River Basin, the Alafia River Basin and the Manatee River Basin, all three of which drain to Tampa Bay (FDEP, Restoring Bacteria-Impaired Waters).

For the Hillsborough River and its neighbors, a BMAP is FDEP's set of permit limits, best management practices and projects meant to reach the pollutant cuts set by a total maximum daily load, and the department says BMAPs are adopted by Secretarial Order and are legally enforceable (FDEP, Basin Management Action Plans).

The Alafia River Basin and the Manatee River Basin each have a 2025 BMAP with a final order effective June 27, 2025, while the Hillsborough River Basin row on the FDEP documents page lists a BMAP and an interactive story map but no 2025 final order (FDEP, BMAP documents). The Nitrogen Management Consortium took up the Alafia, Hillsborough and Manatee River BMAPs at its April 24, 2026, meeting (TBEP), and as of October 18, 2026, the FDEP documents page shows no 2025 or 2026 final order for the Hillsborough River Basin.

One visible Tampa example of high bacteria counts is Sulphur Springs on the Hillsborough River, which the Southwest Florida Water Management District says has been closed for recreation since the mid-1980s because of high bacteria counts (SWFWMD, springs).

The Southwest Florida Water Management District 2024 seagrass map found modest gains in Tampa Bay, the first increase there since 2016, which the district reads as a possible start of recovery from the 2017 to 2019 red tide (SWFWMD, Seagrass Mapping Q and A).

The district calls seagrass a very good indicator of estuarine health and says the depth it grows to is most often set by the light reaching the bottom. The district maps the Suncoast, which runs from Tampa Bay south to Charlotte Harbor, every two years, and the 2024 results come from imagery shot in early 2024, before the 2024 hurricane season (SWFWMD).

That timing matters for anyone reading the 2024 numbers in late 2026: the Tampa Bay map predates the 2024 storms, and the next Suncoast mapping is scheduled for 2026, so the effect of those hurricanes on Tampa Bay seagrass is not yet in any published district map (SWFWMD seagrass page).