We monitor Per- and polyfluoroalkyl substances levels in Hillsborough County’s drinking water to make sure it is safe

The PFAS sampling completed by Hillsborough County is summarized below:

2013-2014 UCMR3 sampling

The County completed PFAS (Per- and polyfluoroalkyl substances) monitoring under the United States Environmental Protection Agency (EPA) Unregulated Contaminant Monitoring Rule 3 (UCMR3). Under UCMR 3 our utility collected samples from our larger water systems for four (4) quarters starting in October 2013 and ending in July 2014.

All Hillsborough County utility samples for PFAS chemicals under UCMR 3 were below the detection levels. The detection levels for PFOA, PFOS, and PFBS for this sampling were:

  1. PFOA / Perfluorooctanoic acid - detection level (parts per trillion): < 20
  2. PFOS / Perfluorooctanesulfonic acid - detection level (parts per trillion): < 40
  3. PFBS / Perfluorobutanesulfonic acid - detection level (parts per trillion): < 90

2019-2020 PFAS sampling

In 2019 and 2020 the County completed additional PFAS monitoring using a newer EPA testing method. This method had lower detection levels with a minimum reporting level at 2.0 parts per trillion. The utility’s sampling consisted of quarterly sampling of our larger systems from June 2019 to February 2020.

The results of the 2019-2020 sampling are summarized below. The monitoring averages are in parts per trillion (ppt):

Hillsborough County South-Central Water System ​

  • PFOA: 4.0 ppt
  • PFOS: 3.4 ppt
  • PFBS: 4.4 ppt

Hillsborough County Northwest Water System ​

  • PFOA: 2.1 ppt
  • PFOS: 2.5 ppt
  • PFBS: 2.1 ppt

Hillsborough County Seaboard Water System ​

  • PFOA: 5.5 ppt
  • PFOS: 4.0 ppt
  • PFBS: 4.6 ppt

2023-2024 PFAS sampling

We are participating in the EPA’s fifth Unregulated Contaminant Monitoring Rule 5 (UCMR 5) during 2023-2024 to further test for PFAS chemicals. This involves testing four of Hillsborough County’s drinking water systems for PFAS using the EPA’s approved analytical methods.

This sampling is ongoing and is summarized here: UCMR 5 PFAS Summary Table


Are PFAS regulated?

The EPA and the state of Florida have not yet regulated PFAS in drinking water; however, in March 2023, the EPA took a step forward in the regulation process and announced proposed Maximum Contaminant Levels for PFOA and PFOS at 4 parts per trillion (ppt). EPA is expected to release final Maximum Contaminant Levels by the end of 2023.

How can PFAS get into drinking water?

PFAS do not originate in drinking water. PFAS are slow to break down in the environment and can move far from their original use areas. The manufacturing, use, and discarding of these products put PFAS into the environment, where, over time, they may end up in drinking water sources.

More information

More information can be found at the US EPA, Tampa Bay Water, and Florida Department of Health sites below:


Ask a question or reach out with a concern. We are always available to talk about how Hillsborough County produces and delivers your drinking water and the steps the County takes to maintain quality. Please contact us at (813) 246-3146.

Last Modified: 2/16/2024, 6:08:41 PM

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