Gcwsd Kilsock Water Sys (Sc2220002)

PFAS monitoring results for a public water system in South Carolina

SC2220002UCMR 5EPA monitoring data
<MRLHighest PFOA result, ppt
<MRLHighest PFOS result, ppt
0Highest Hazard Index
300Results
PWSID
SC2220002
State
South Carolina
System type
community water system (CWS)
Population served
4,417
City
Pawleys Island
Counties
Georgetown County
Primary source water
groundwater
UCMR 5 sampling
2023-06-19 to 2024-11-05 · 5 entry point(s) · water types: GW
Service-area boundary
EPA-modeled (Random Forest) — approximate: estimated by EPA with a statistical model, not a surveyed service area

No PFAS detected highest single result
No PFAS detected 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.

Compared with EPA's 2024 values

Highest single resultWorst entry-point average*Limit
PFOA (ppt)<MRL04
PFOS (ppt)<MRL04
Hazard Index001.0†

“<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).

No South Carolina PFAS drinking-water standard in effect or proposed as of 2026-10-17: No state PFAS drinking-water standard; H. 3116 and H. 5572 (2025-26) pending, not enacted.

Sampling history

Sampled 2023-06-19 to 2024-11-05 · 5 entry point(s) · water types: GW · 17 sampling visits. PFAS in ppt (ng/L).

DateEntry pointEventPFOAPFOSHIOther detections
2023-06-19GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE1<4<40lithium 16.2 µg/L
2023-06-19GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE1<4<40lithium 13.7 µg/L
2023-06-19GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE1<4<40lithium 17.2 µg/L
2023-06-19GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE1<4<40lithium 16.8 µg/L
2023-06-19GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE1<4<40lithium 11.9 µg/L
2023-07-11GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE1n/an/an/anone
2023-07-11GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE1n/an/an/anone
2023-12-11GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2<4<40lithium 9.8 µg/L
2023-12-11GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2n/an/an/alithium 11 µg/L
2023-12-11GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2n/an/an/alithium 13 µg/L
2023-12-11GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2n/an/an/alithium 13 µg/L
2024-01-23GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2<4<40none
2024-01-23GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2<4<40none
2024-01-30GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2n/an/an/anone
2024-08-20GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2<4<40none
2024-08-20GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2n/an/an/anone
2024-11-05GCWSD KILSOCK WATER SYS (SC2220002) (GW)SE2<4<40none

“<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.

GCWSD KILSOCK WATER SYS (SC2220002) facility B22001 · sample point B22001 · groundwater

CompoundMRL2023-06-19
SE1
2023-12-11
SE2
2024-01-23
SE2
2024-01-30
SE2
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–
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/L16.213––

GCWSD KILSOCK WATER SYS (SC2220002) facility B22003 · sample point B22003 · groundwater

CompoundMRL2023-06-19
SE1
2023-12-11
SE2
2024-01-23
SE2
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
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/L13.711–

GCWSD KILSOCK WATER SYS (SC2220002) facility B22013 · sample point B22013 · groundwater

CompoundMRL2023-06-19
SE1
2023-07-11
SE1
2023-12-11
SE2
2024-08-20
SE2
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
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/L17.2–13–

GCWSD KILSOCK WATER SYS (SC2220002) facility B22014 · sample point B22014 · groundwater

CompoundMRL2023-06-19
SE1
2023-07-11
SE1
2024-08-20
SE2
2024-11-05
SE2
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
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/L16.8–< 9–

GCWSD KILSOCK WATER SYS (SC2220002) facility B22018 · sample point B22018 · groundwater

CompoundMRL2023-06-19
SE1
2023-12-11
SE2
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
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/L11.99.8

Statistics by compound

CompoundResultsDetectedHighest (date)Mean boundsKM medianP75P90P95
lithium1090%17.2
2023-06-19
12.26–13.161316.216.817.2

Never detected (29): 11Cl-PF3OUdS, 4:2 FTS, 6:2 FTS, 8:2 FTS, 9Cl-PF3ONS, ADONA, HFPO-DA, NEtFOSAA, NFDHA, NMeFOSAA, PFBA, PFBS, PFDA, PFDoA, PFEESA, PFHpA, PFHpS, PFHxA, PFHxS, PFMBA, PFMPA, PFNA, PFOA, PFOS, PFPeA, PFPeS, PFTA, PFTrDA, PFUnA.

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 2026-06-15; 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 04c4b5704fe9 · 2026-10-18T04:07Z · UCMR 5 release Jul2026 · SDWIS 2026Q3. Data and methods.