Walker County Water Authority

PFAS monitoring results for a public water system in Georgia

GA2950003UCMR 5EPA monitoring data
12Highest PFOA result, ppt
22Highest PFOS result, ppt
0.015Highest Hazard Index
300Results
PWSID
GA2950003
State
Georgia
System type
community water system (CWS)
Population served
36,000
City
Flintstone
Counties
Walker County
Primary source water
surface water
UCMR 5 sampling
2024-03-06 to 2024-12-11 · 4 entry point(s) · water types: GW;SW
Service-area boundary
authoritative

PFOS ≥ 3 × its limit highest single result
PFOS 1–3 × its limit worst entry-point average

These are monitoring results collected under EPA's Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) at entry points, where treated water enters the distribution system; they are not tap-water samples. They are not compliance determinations: compliance with EPA's 2024 PFAS limits is judged on running annual averages of compliance monitoring, required from 2029, so a single UCMR 5 result at or above a limit is not a violation. “< MRL” means the compound was not quantified at EPA's minimum reporting level; it does not mean zero.

Water purchased from

Seller results are the seller's own entry-point samples, not measurements of this system's water. This system's own samples (below) may reflect purchased water, its own sources, or both.

Compared with EPA's 2024 values

Highest single resultWorst entry-point average*Limit
PFOA (ppt)127.14
PFOS (ppt)2210.954
Hazard Index0.0150.0131.0†

“<MRL” = every result for the compound was below its reporting limit. * Mean of all samples at each entry point with non-detects = 0 (EPA compliance convention; the Hazard Index also uses non-detects = 0); a screening comparison, not a formal running annual average. † Rescission proposed May 2026. PFOA/PFOS MCL 4 ppt (2024 NPDWR, in effect). PFHxS, PFNA, HFPO-DA (10 ppt each) and the Hazard Index (1.0) are 2024 NPDWR values; EPA proposed rescinding them on 18 May 2026 (comment period closed 20 Jul 2026).

Sampling history

Sampled 2024-03-06 to 2024-12-11 · 4 entry point(s) · water types: GW;SW · 10 sampling visits. PFAS in ppt (ng/L).

DateEntry pointEventPFOAPFOSHIOther detections
2024-03-06Coke Ovens Wells Plant (GW)SE18.6130.013PFHxA 3.4, PFPeA 4.5
2024-03-06Kensington Wells Plant (GW)SE1<4<406:2 FTS 5.1
2024-03-06Walker County Water Plant (SW)SE16.340.014PFHxA 3.5, PFPeA 4.9
2024-03-06Well #4 TP (GW)SE16.34.20.013PFHxA 3.4, PFPeA 4.6
2024-06-05Walker County Water Plant (SW)SE25.3<40.015PFPeA 3.7
2024-09-09Walker County Water Plant (SW)SE3<4<40.007PFPeA 3.3
2024-09-10Coke Ovens Wells Plant (GW)SE25.68.90.008PFPeA 3.3
2024-09-10Kensington Wells Plant (GW)SE2<4<40none
2024-09-10Well #4 TP (GW)SE2<4<40.008PFPeA 3.5
2024-12-11Walker County Water Plant (SW)SE412220.013PFHpA 3.8, PFHxA 4.7, PFPeA 6.9

“<4” = not detected at the reporting limit shown; “n/a” = not analyzed in that sample. Highlighted = at or above the 4 ppt MCL. HI computed per sample with non-detects as 0. Other detections lists every other quantified compound (lithium in µg/L).

All results by entry point

300 results. Each column is one sampling visit (date and UCMR 5 sample event). A number is a measured concentration; “< 4” = below the minimum reporting level shown; “–” = not analyzed in that visit. PFAS in ppt (ng/L); lithium in µg/L.

Coke Ovens Wells Plant facility 03254 · sample point 302 · groundwater

CompoundMRL2024-03-06
SE1
2024-09-10
SE2
PFBS3 ppt2516
PFHxA3 ppt3.4< 3
PFOA4 ppt8.65.6
PFOS4 ppt138.9
PFPeA3 ppt4.53.3
11Cl-PF3OUdS5 ppt< 5< 5
4:2 FTS3 ppt< 3< 3
6:2 FTS5 ppt< 5< 5
8:2 FTS5 ppt< 5< 5
9Cl-PF3ONS2 ppt< 2< 2
ADONA3 ppt< 3< 3
HFPO-DA5 ppt< 5< 5
NEtFOSAA5 ppt< 5< 5
NFDHA20 ppt< 20< 20
NMeFOSAA6 ppt< 6< 6
PFBA5 ppt< 5< 5
PFDA3 ppt< 3< 3
PFDoA3 ppt< 3< 3
PFEESA3 ppt< 3< 3
PFHpA3 ppt< 3< 3
PFHpS3 ppt< 3< 3
PFHxS3 ppt< 3< 3
PFMBA3 ppt< 3< 3
PFMPA4 ppt< 4< 4
PFNA4 ppt< 4< 4
PFPeS4 ppt< 4< 4
PFTA8 ppt< 8< 8
PFTrDA7 ppt< 7< 7
PFUnA2 ppt< 2< 2
lithium9 µg/L< 9< 9

Kensington Wells Plant facility 03581 · sample point 303 · groundwater

CompoundMRL2024-03-06
SE1
2024-09-10
SE2
6:2 FTS5 ppt5.1< 5
11Cl-PF3OUdS5 ppt< 5< 5
4:2 FTS3 ppt< 3< 3
8:2 FTS5 ppt< 5< 5
9Cl-PF3ONS2 ppt< 2< 2
ADONA3 ppt< 3< 3
HFPO-DA5 ppt< 5< 5
NEtFOSAA5 ppt< 5< 5
NFDHA20 ppt< 20< 20
NMeFOSAA6 ppt< 6< 6
PFBA5 ppt< 5< 5
PFBS3 ppt< 3< 3
PFDA3 ppt< 3< 3
PFDoA3 ppt< 3< 3
PFEESA3 ppt< 3< 3
PFHpA3 ppt< 3< 3
PFHpS3 ppt< 3< 3
PFHxA3 ppt< 3< 3
PFHxS3 ppt< 3< 3
PFMBA3 ppt< 3< 3
PFMPA4 ppt< 4< 4
PFNA4 ppt< 4< 4
PFOA4 ppt< 4< 4
PFOS4 ppt< 4< 4
PFPeA3 ppt< 3< 3
PFPeS4 ppt< 4< 4
PFTA8 ppt< 8< 8
PFTrDA7 ppt< 7< 7
PFUnA2 ppt< 2< 2
lithium9 µg/L< 9< 9

Walker County Water Plant facility 02409 · sample point 301 · surface water

CompoundMRL2024-03-06
SE1
2024-06-05
SE2
2024-09-09
SE3
2024-12-11
SE4
PFBS3 ppt28311526
PFHpA3 ppt< 3< 3< 33.8
PFHxA3 ppt3.5< 3< 34.7
PFOA4 ppt6.35.3< 412
PFOS4 ppt4< 4< 422
PFPeA3 ppt4.93.73.36.9
11Cl-PF3OUdS5 ppt< 5< 5< 5< 5
4:2 FTS3 ppt< 3< 3< 3< 3
6:2 FTS5 ppt< 5< 5< 5< 5
8:2 FTS5 ppt< 5< 5< 5< 5
9Cl-PF3ONS2 ppt< 2< 2< 2< 2
ADONA3 ppt< 3< 3< 3< 3
HFPO-DA5 ppt< 5< 5< 5< 5
NEtFOSAA5 ppt< 5< 5< 5< 5
NFDHA20 ppt< 20< 20< 20< 20
NMeFOSAA6 ppt< 6< 6< 6< 6
PFBA5 ppt< 5< 5< 5< 5
PFDA3 ppt< 3< 3< 3< 3
PFDoA3 ppt< 3< 3< 3< 3
PFEESA3 ppt< 3< 3< 3< 3
PFHpS3 ppt< 3< 3< 3< 3
PFHxS3 ppt< 3< 3< 3< 3
PFMBA3 ppt< 3< 3< 3< 3
PFMPA4 ppt< 4< 4< 4< 4
PFNA4 ppt< 4< 4< 4< 4
PFPeS4 ppt< 4< 4< 4< 4
PFTA8 ppt< 8< 8< 8< 8
PFTrDA7 ppt< 7< 7< 7< 7
PFUnA2 ppt< 2< 2< 2< 2
lithium9 µg/L< 9< 9< 9< 9

Well #4 TP facility 21250 · sample point 304 · groundwater

CompoundMRL2024-03-06
SE1
2024-09-10
SE2
PFBS3 ppt2716
PFHxA3 ppt3.4< 3
PFOA4 ppt6.3< 4
PFOS4 ppt4.2< 4
PFPeA3 ppt4.63.5
11Cl-PF3OUdS5 ppt< 5< 5
4:2 FTS3 ppt< 3< 3
6:2 FTS5 ppt< 5< 5
8:2 FTS5 ppt< 5< 5
9Cl-PF3ONS2 ppt< 2< 2
ADONA3 ppt< 3< 3
HFPO-DA5 ppt< 5< 5
NEtFOSAA5 ppt< 5< 5
NFDHA20 ppt< 20< 20
NMeFOSAA6 ppt< 6< 6
PFBA5 ppt< 5< 5
PFDA3 ppt< 3< 3
PFDoA3 ppt< 3< 3
PFEESA3 ppt< 3< 3
PFHpA3 ppt< 3< 3
PFHpS3 ppt< 3< 3
PFHxS3 ppt< 3< 3
PFMBA3 ppt< 3< 3
PFMPA4 ppt< 4< 4
PFNA4 ppt< 4< 4
PFPeS4 ppt< 4< 4
PFTA8 ppt< 8< 8
PFTrDA7 ppt< 7< 7
PFUnA2 ppt< 2< 2
lithium9 µg/L< 9< 9

Statistics by compound

CompoundResultsDetectedHighest (date)Mean boundsKM medianP75P90P95
PFBS1080%31
2024-06-05
18.4–1916272831
PFPeA1080%6.9
2024-12-11
3.47–4.073.54.64.96.9
PFOA1060%12
2024-12-11
4.41–6.015.36.38.612
PFOS1050%22
2024-12-11
5.21–7.21<MRL8.91322
PFHxA1040%4.7
2024-12-11
1.5–3.3<MRL3.43.54.7
6:2 FTS1010%5.1
2024-03-06
0.51–5.01<MRL<MRL<MRL5.1
PFHpA1010%3.8
2024-12-11
0.38–3.08<MRL<MRL<MRL3.8

Never detected (23): 11Cl-PF3OUdS, 4:2 FTS, 8:2 FTS, 9Cl-PF3ONS, ADONA, HFPO-DA, NEtFOSAA, NFDHA, NMeFOSAA, PFBA, PFDA, PFDoA, PFEESA, PFHpS, PFHxS, PFMBA, PFMPA, PFNA, PFPeS, PFTA, PFTrDA, PFUnA, lithium.

Left-censored Kaplan–Meier statistics (Helsel 2005; Helsel & Lee 2006, NADA for R). Units: ppt; lithium µg/L. Each compound has one reporting limit, so the Kaplan–Meier mean equals the upper mean bound (non-detects at the MRL); the lower bound sets non-detects to 0. “<MRL” = the percentile falls below the reporting limit and cannot be estimated. These describe this system's UCMR 5 samples, not population estimates.

Sources

  • EPA UCMR 5 occurrence data text files (UCMR5_All.txt; samples 2023-01-09 to 2026-06-17; data summary dated Jul 2026)
  • EPA SDWIS via ECHO SDWA downloads, quarter 2026Q3
  • EPA Public Water System Service Areas v3 (Mar 2026)
  • US Census Bureau cartographic boundary counties 1:500k, 2024
  • EPA/USGS NHDPlus V2 (medium resolution) flowlines, Strahler order 2+

Data build e0e919e2a26a · 2026-10-18T04:09Z · UCMR 5 release Jul2026 · SDWIS 2026Q3. Data and methods.