Mississippi PFAS results from EPA's final data
Report published Nov 14, 2026 · EPA UCMR 5 final data file of Oct 15, 2026 (samples collected 2023–2025) · Method · National results →
5 Mississippi water systems serving 84,633 people had PFAS above a 2024 federal limit in EPA's final round of nationwide PFAS testing: 2% of the 235 Mississippi systems tested, compared with 11% nationally.
Highest PFOA or PFOS averages in Mississippi
- City of Oxford Oxford · PFOS52.9 ppt
- City of Holly Springs Holly Springs · PFOS9.45 ppt
- Smiths Crossing Water Association Magee · PFOS5.4 ppt
- University of Mississippi Water System University · PFOA5.3 ppt
- City of Corinth Corinth · PFOS5.28 ppt
- Keesler Air Force Base Water System Biloxi · PFOS3.85 ppt
- Sunrise Utility Association Inc Petal · PFOA2.75 ppt
Chart data as a table
| System | ppt |
|---|---|
| City of Oxford · Oxford · PFOS | 52.9 |
| City of Holly Springs · Holly Springs · PFOS | 9.45 |
| Smiths Crossing Water Association · Magee · PFOS | 5.4 |
| University of Mississippi Water System · University · PFOA | 5.3 |
| City of Corinth · Corinth · PFOS | 5.28 |
| Keesler Air Force Base Water System · Biloxi · PFOS | 3.85 |
| Sunrise Utility Association Inc · Petal · PFOA | 2.75 |
Largest systems above a limit
| # | System | People served |
|---|---|---|
| 1 | City of Oxford Oxford Above: PFOA, PFOS | 28,500 |
| 2 | University of Mississippi Water System University Above: PFOA | 26,874 |
| 3 | City of Corinth Corinth Above: PFOA, PFOS | 15,000 |
| 4 | City of Holly Springs Holly Springs Above: PFOA, PFOS | 9,779 |
| 5 | Smiths Crossing Water Association Magee Above: PFOS | 4,480 |
Which limits were exceeded
| PFAS | Federal limit | Systems above it |
|---|---|---|
| PFOA 80,153 people | 4 ppt | 4 |
| PFOS 57,759 people | 4 ppt | 4 |
| PFHxS | 10 ppt | 0 |
| PFNA | 10 ppt | 0 |
| GenX (HFPO-DA) | 10 ppt | 0 |
| Hazard Index | 1 | 0 |
"–" in the table above means not detected. A system can be above more than one limit. EPA proposed in May 2026 to rescind the PFHxS, PFNA, GenX and Hazard Index limits. That proposal is not final.
Data and how to cite it
- Download every Mississippi water system as CSV (PFOA and PFOS averages, systems above a limit, lead, violations).
- EPA's source file: UCMR 5 occurrence data.
Suggested citation:
Tap Water Results, "Mississippi PFAS results from EPA's final UCMR 5 data" (published Nov 14, 2026, EPA data file of Oct 15, 2026). https://tapwaterresults.com/pfas/mississippi/
You're welcome to quote and republish these figures with a link back. Questions from reporters: see contact.
Method
For each system we average each entry point's UCMR 5 results (non-detects count as zero, complete sets of samples only) and compare the highest entry-point average with the 2024 federal limit, using EPA's rounding. This is how EPA compares UCMR 5 results to the limits in its own data summary, and our national counts match EPA's published table within 2% (how we check). Results are monitoring data from 2023–2025, not compliance determinations, and treatment installed since then is not reflected. Full method.
Questions
How many Mississippi water systems have PFAS above the limit?
5 of the 235 Mississippi community water systems EPA tested in 2023–2025 (2%) had at least one entry-point average above a 2024 federal PFAS limit. They serve 84,633 people. Nationally the share is 11%.
Are these systems violating the law?
Not yet. Systems have until 2029 to meet the 2024 limits, and EPA has proposed moving the PFOA and PFOS deadline to 2031 and rescinding the other limits. EPA's UCMR 5 results are monitoring data and do not determine compliance.
Which systems were tested?
EPA's UCMR 5 tested every community water system serving more than 3,300 people and a representative sample of smaller ones. Systems that were not tested have no federal result, which is not the same as having no PFAS.
All Mississippi water systems → · National results → · PFAS results for every state →
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.