- PWSID
- IL1970250
- State
- Illinois
- System type
- community water system (CWS)
- Population served
- 20,223
- City
- Crest Hill
- Counties
- Will County
- Primary source water
- groundwater
- UCMR 5 sampling
- 2023-06-12 to 2023-12-28 · 7 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
PFOA ≥ 3 × its limit highest single result
PFOA ≥ 3 × its limit worst entry-point average
Open on the Illinois map · All Illinois systems · All results
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 result | Worst entry-point average* | Limit | |
|---|---|---|---|
| PFOA (ppt) | 13.7 | 12.4 | 4 |
| PFOS (ppt) | <MRL | 0 | 4 |
| Hazard Index | 1.222 | 1.107 | 1.0† |
“<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).
Compared with Illinois standards
| Highest single result | Worst entry-point average* | Illinois | |
|---|---|---|---|
| PFOA (ppt) | 13.7 | 12.4 | 4 |
| PFOS (ppt) | 0 | 0 | 4 |
| PFNA (ppt) | 0 | 0 | 10 |
| PFHxS (ppt) | 12.2 | 11.05 | 10 |
| HFPO-DA (GenX) (ppt) | 0 | 0 | 10 |
Sum standards add the listed compounds within each sample (non-detects = 0). State compliance is normally judged on averages over time; these are screening comparisons.
Sampling history
Sampled 2023-06-12 to 2023-12-28 · 7 entry point(s) · water types: GW · 14 sampling visits. PFAS in ppt (ng/L).
| Date | Entry point | Event | PFOA | PFOS | HI | Other detections |
|---|---|---|---|---|---|---|
| 2023-06-12 | TP 1 (Well 1) (GW) | SE1 | 11.1 | <4 | 0.524 | PFBA 12.5, PFHpA 10, PFHxA 15.1, PFPeA 17.3, lithium 34.3 µg/L |
| 2023-06-12 | TP 3 (Well 4) (GW) | SE1 | <4 | <4 | 0.992 | PFHxA 3.5, PFPeA 4.9, lithium 28.5 µg/L |
| 2023-06-12 | TP 5 (Well 7) (GW) | SE1 | 7.6 | <4 | 0.471 | PFBA 10.1, PFHpA 7.6, PFHxA 11.6, PFPeA 13.4, lithium 33.9 µg/L |
| 2023-06-12 | TP 6 (Well 8) (GW) | SE1 | <4 | <4 | 0.582 | PFBA 5.1, PFHxA 5.5, PFPeA 6.8, lithium 21.7 µg/L |
| 2023-06-12 | TP 7 (Wells 9 & 12) (GW) | SE1 | <4 | <4 | 0.003 | lithium 30.5 µg/L |
| 2023-06-12 | TP 8 (Well 10) (GW) | SE1 | 10.5 | <4 | 0.436 | PFBA 27.2, PFHpA 11.8, PFHxA 24.4, PFPeA 32.2, lithium 27.4 µg/L |
| 2023-06-12 | TP 9 (Well 11) (GW) | SE1 | <4 | <4 | 0.003 | PFPeA 3.2, lithium 29.6 µg/L |
| 2023-12-28 | TP 1 (Well 1) (GW) | SE2 | 13.7 | <4 | 0.682 | PFBA 18.8, PFHpA 13.3, PFHxA 22.3, PFPeA 25.9, lithium 33.5 µg/L |
| 2023-12-28 | TP 3 (Well 4) (GW) | SE2 | <4 | <4 | 1.222 | PFBA 5, PFHxA 4.7, PFPeA 6.8, lithium 29 µg/L |
| 2023-12-28 | TP 5 (Well 7) (GW) | SE2 | 5.8 | <4 | 0.429 | PFBA 8.9, PFHpA 5.9, PFHxA 9.9, PFPeA 11.8, lithium 34.8 µg/L |
| 2023-12-28 | TP 6 (Well 8) (GW) | SE2 | <4 | <4 | 0.423 | PFBA 5.6, PFHxA 6.2, PFPeA 7.5, lithium 20.1 µg/L |
| 2023-12-28 | TP 7 (Wells 9 & 12) (GW) | SE2 | <4 | <4 | 0.004 | lithium 32.1 µg/L |
| 2023-12-28 | TP 8 (Well 10) (GW) | SE2 | 4.6 | <4 | 0.014 | PFBA 15.1, PFHpA 5.3, PFHxA 12.1, PFPeA 17, lithium 30.4 µg/L |
| 2023-12-28 | TP 9 (Well 11) (GW) | SE2 | <4 | <4 | 0.005 | PFBA 5.9, PFHxA 3.6, PFPeA 5.7, lithium 30.3 µg/L |
“<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
420 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.
TP 1 (Well 1) facility 00001 · sample point TP01 · groundwater
| Compound | MRL | 2023-06-12 SE1 | 2023-12-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 12.5 | 18.8 |
| PFBS | 3 ppt | 27.8 | 43.7 |
| PFHpA | 3 ppt | 10 | 13.3 |
| PFHxA | 3 ppt | 15.1 | 22.3 |
| PFHxS | 3 ppt | 5.1 | 6.6 |
| PFOA | 4 ppt | 11.1 | 13.7 |
| PFPeA | 3 ppt | 17.3 | 25.9 |
| 11Cl-PF3OUdS | 5 ppt | < 5 | < 5 |
| 4:2 FTS | 3 ppt | < 3 | < 3 |
| 6:2 FTS | 5 ppt | < 5 | < 5 |
| 8:2 FTS | 5 ppt | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 | < 2 |
| ADONA | 3 ppt | < 3 | < 3 |
| HFPO-DA | 5 ppt | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | < 5 |
| NFDHA | 20 ppt | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | < 6 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | 34.3 | 33.5 |
TP 3 (Well 4) facility 00003 · sample point TP03 · groundwater
| Compound | MRL | 2023-06-12 SE1 | 2023-12-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | < 5 | 5 |
| PFBS | 3 ppt | 3.3 | 3.9 |
| PFHxA | 3 ppt | 3.5 | 4.7 |
| PFHxS | 3 ppt | 9.9 | 12.2 |
| PFPeA | 3 ppt | 4.9 | 6.8 |
| 11Cl-PF3OUdS | 5 ppt | < 5 | < 5 |
| 4:2 FTS | 3 ppt | < 3 | < 3 |
| 6:2 FTS | 5 ppt | < 5 | < 5 |
| 8:2 FTS | 5 ppt | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 | < 2 |
| ADONA | 3 ppt | < 3 | < 3 |
| HFPO-DA | 5 ppt | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | < 5 |
| NFDHA | 20 ppt | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | < 6 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | 28.5 | 29 |
TP 5 (Well 7) facility 00005 · sample point TP05 · groundwater
| Compound | MRL | 2023-06-12 SE1 | 2023-12-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 10.1 | 8.9 |
| PFBS | 3 ppt | 21.5 | 17.5 |
| PFHpA | 3 ppt | 7.6 | 5.9 |
| PFHxA | 3 ppt | 11.6 | 9.9 |
| PFHxS | 3 ppt | 4.6 | 4.2 |
| PFOA | 4 ppt | 7.6 | 5.8 |
| PFPeA | 3 ppt | 13.4 | 11.8 |
| 11Cl-PF3OUdS | 5 ppt | < 5 | < 5 |
| 4:2 FTS | 3 ppt | < 3 | < 3 |
| 6:2 FTS | 5 ppt | < 5 | < 5 |
| 8:2 FTS | 5 ppt | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 | < 2 |
| ADONA | 3 ppt | < 3 | < 3 |
| HFPO-DA | 5 ppt | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | < 5 |
| NFDHA | 20 ppt | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | < 6 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | 33.9 | 34.8 |
TP 6 (Well 8) facility 00006 · sample point TP06 · groundwater
| Compound | MRL | 2023-06-12 SE1 | 2023-12-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 5.1 | 5.6 |
| PFBS | 3 ppt | 4.2 | 5.9 |
| PFHxA | 3 ppt | 5.5 | 6.2 |
| PFHxS | 3 ppt | 5.8 | 4.2 |
| PFPeA | 3 ppt | 6.8 | 7.5 |
| 11Cl-PF3OUdS | 5 ppt | < 5 | < 5 |
| 4:2 FTS | 3 ppt | < 3 | < 3 |
| 6:2 FTS | 5 ppt | < 5 | < 5 |
| 8:2 FTS | 5 ppt | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 | < 2 |
| ADONA | 3 ppt | < 3 | < 3 |
| HFPO-DA | 5 ppt | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | < 5 |
| NFDHA | 20 ppt | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | < 6 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | 21.7 | 20.1 |
TP 7 (Wells 9 & 12) facility 00007 · sample point TP07 · groundwater
| Compound | MRL | 2023-06-12 SE1 | 2023-12-28 SE2 |
|---|---|---|---|
| PFBS | 3 ppt | 5.1 | 7.9 |
| 11Cl-PF3OUdS | 5 ppt | < 5 | < 5 |
| 4:2 FTS | 3 ppt | < 3 | < 3 |
| 6:2 FTS | 5 ppt | < 5 | < 5 |
| 8:2 FTS | 5 ppt | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 | < 2 |
| ADONA | 3 ppt | < 3 | < 3 |
| HFPO-DA | 5 ppt | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | < 5 |
| NFDHA | 20 ppt | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | < 6 |
| PFBA | 5 ppt | < 5 | < 5 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFHxA | 3 ppt | < 3 | < 3 |
| PFHxS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| PFPeA | 3 ppt | < 3 | < 3 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | 30.5 | 32.1 |
TP 8 (Well 10) facility 00008 · sample point TP08 · groundwater
| Compound | MRL | 2023-06-12 SE1 | 2023-12-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | 27.2 | 15.1 |
| PFBS | 3 ppt | 52.1 | 28.5 |
| PFHpA | 3 ppt | 11.8 | 5.3 |
| PFHxA | 3 ppt | 24.4 | 12.1 |
| PFHxS | 3 ppt | 4.1 | < 3 |
| PFOA | 4 ppt | 10.5 | 4.6 |
| PFPeA | 3 ppt | 32.2 | 17 |
| 11Cl-PF3OUdS | 5 ppt | < 5 | < 5 |
| 4:2 FTS | 3 ppt | < 3 | < 3 |
| 6:2 FTS | 5 ppt | < 5 | < 5 |
| 8:2 FTS | 5 ppt | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 | < 2 |
| ADONA | 3 ppt | < 3 | < 3 |
| HFPO-DA | 5 ppt | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | < 5 |
| NFDHA | 20 ppt | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | < 6 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | 27.4 | 30.4 |
TP 9 (Well 11) facility 00009 · sample point TP09 · groundwater
| Compound | MRL | 2023-06-12 SE1 | 2023-12-28 SE2 |
|---|---|---|---|
| PFBA | 5 ppt | < 5 | 5.9 |
| PFBS | 3 ppt | 6.4 | 9.8 |
| PFHxA | 3 ppt | < 3 | 3.6 |
| PFPeA | 3 ppt | 3.2 | 5.7 |
| 11Cl-PF3OUdS | 5 ppt | < 5 | < 5 |
| 4:2 FTS | 3 ppt | < 3 | < 3 |
| 6:2 FTS | 5 ppt | < 5 | < 5 |
| 8:2 FTS | 5 ppt | < 5 | < 5 |
| 9Cl-PF3ONS | 2 ppt | < 2 | < 2 |
| ADONA | 3 ppt | < 3 | < 3 |
| HFPO-DA | 5 ppt | < 5 | < 5 |
| NEtFOSAA | 5 ppt | < 5 | < 5 |
| NFDHA | 20 ppt | < 20 | < 20 |
| NMeFOSAA | 6 ppt | < 6 | < 6 |
| PFDA | 3 ppt | < 3 | < 3 |
| PFDoA | 3 ppt | < 3 | < 3 |
| PFEESA | 3 ppt | < 3 | < 3 |
| PFHpA | 3 ppt | < 3 | < 3 |
| PFHpS | 3 ppt | < 3 | < 3 |
| PFHxS | 3 ppt | < 3 | < 3 |
| PFMBA | 3 ppt | < 3 | < 3 |
| PFMPA | 4 ppt | < 4 | < 4 |
| PFNA | 4 ppt | < 4 | < 4 |
| PFOA | 4 ppt | < 4 | < 4 |
| PFOS | 4 ppt | < 4 | < 4 |
| PFPeS | 4 ppt | < 4 | < 4 |
| PFTA | 8 ppt | < 8 | < 8 |
| PFTrDA | 7 ppt | < 7 | < 7 |
| PFUnA | 2 ppt | < 2 | < 2 |
| lithium | 9 µg/L | 29.6 | 30.3 |
Statistics by compound
| Compound | Results | Detected | Highest (date) | Mean bounds | KM median | P75 | P90 | P95 |
|---|---|---|---|---|---|---|---|---|
| PFBS | 14 | 100% | 52.1 2023-06-12 | 16.97–16.97 | 7.9 | 27.8 | 43.7 | 52.1 |
| lithium | 14 | 100% | 34.8 2023-12-28 | 29.72–29.72 | 30.3 | 33.5 | 34.3 | 34.8 |
| PFPeA | 14 | 86% | 32.2 2023-06-12 | 10.89–11.32 | 6.8 | 17 | 25.9 | 32.2 |
| PFHxA | 14 | 79% | 24.4 2023-06-12 | 8.49–9.14 | 5.5 | 12.1 | 22.3 | 24.4 |
| PFBA | 14 | 71% | 27.2 2023-06-12 | 8.16–9.59 | 5.6 | 12.5 | 18.8 | 27.2 |
| PFHxS | 14 | 64% | 12.2 2023-12-28 | 4.05–5.12 | 4.2 | 5.8 | 9.9 | 12.2 |
| PFHpA | 14 | 43% | 13.3 2023-12-28 | 3.85–5.56 | <MRL | 7.6 | 11.8 | 13.3 |
| PFOA | 14 | 43% | 13.7 2023-12-28 | 3.81–6.09 | <MRL | 7.6 | 11.1 | 13.7 |
Never detected (22): 11Cl-PF3OUdS, 4:2 FTS, 6:2 FTS, 8:2 FTS, 9Cl-PF3ONS, ADONA, HFPO-DA, NEtFOSAA, NFDHA, NMeFOSAA, PFDA, PFDoA, PFEESA, PFHpS, PFMBA, PFMPA, PFNA, PFOS, 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 2026-04-22; 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 85f0496a668b · 2026-10-18T04:10Z · UCMR 5 release Jul2026 · SDWIS 2026Q3. Data and methods.