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Updated 2026-10-15
County water report

Cook County Water Quality: 71 Cities Ranked by the Records

Cook County, Illinois: 71 city reports built from EPA and utility records. A county has many suppliers; each city shows the system that serves it.

Find my systemOpen on the mapPrivate wells in Cook County
Across the county's systems

Highest result for each contaminant

One row per contaminant: the highest result any system in the county reported, against its limit. Open a row for the systems behind it.

LithiumDetected in 5 systems of 71 tested10 µg/L EPA health reference level (screening, not a legal limit) · US EPAHighest90 µg/L
  • RICHTON PARK90 µg/LSample date: 2024-02-13 to 2024-08-13
  • WESTERN SPRINGS66.7 µg/LSample date: 2023-10-11 to 2024-04-16
  • LEMONT53.8 µg/LSample date: 2024-03-07 to 2024-09-12
  • PARK FOREST21.5 µg/LSample date: 2025-01-07 to 2025-07-16
  • BARRINGTON12 µg/LSample date: 2023-02-09 to 2023-08-15
  • ALSIPNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-07-10 to 2025-04-15
  • ARLINGTON HEIGHTSNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-12-12 to 2024-09-24
  • BELLWOODNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-10-31 to 2026-02-05
  • BERWYNNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-11-21 to 2025-02-25
  • BLUE ISLANDNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-07-24 to 2024-03-27
  • BRIDGEVIEWNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-09-18 to 2024-06-20
  • BROOKFIELDNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-02-12 to 2024-12-23
  • CALUMET CITYNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-06-28 to 2024-06-04
  • CHICAGONot detected · below 9.0 µg/L lab reporting limitSample date: 2024-01-08 to 2024-10-08
  • CHICAGO HEIGHTSNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-09-17 to 2025-06-03
  • CHICAGO RIDGENot detected · below 9.0 µg/L lab reporting limitSample date: 2024-07-17 to 2025-04-09
  • CICERONot detected · below 9.0 µg/L lab reporting limitSample date: 2023-01-25 to 2024-02-08
  • COUNTRY CLUB HILLSNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-12-05 to 2025-09-04
  • CRESTWOODNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-07-22 to 2026-04-22
  • DES PLAINESNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-05-06 to 2025-02-13
  • DOLTONNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-01-28 to 2026-01-28
  • ELK GROVE VILLAGENot detected · below 9.0 µg/L lab reporting limitSample date: 2024-11-19 to 2025-08-13
  • ELMWOOD PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-11-14 to 2025-09-10
  • EVANSTONNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-06-06 to 2024-03-07
  • EVERGREEN PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-04-19 to 2024-01-17
  • FOREST PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-04-11 to 2025-02-03
  • FRANKLIN PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-07-26 to 2024-04-09
  • GLENVIEWNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-11-07 to 2025-08-19
  • HARVEYNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-09-12 to 2024-06-11
  • HAZEL CRESTNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-10-10 to 2025-07-09
  • HICKORY HILLSNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-06-18 to 2025-03-18
  • HOFFMAN ESTATESNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-03-21 to 2023-12-05
  • HOMEWOODNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-09-19 to 2024-06-05
  • JUSTICE-WILLOW SPRINGS WATER COMMISSIONNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-02-13 to 2025-11-20
  • LA GRANGENot detected · below 9.0 µg/L lab reporting limitSample date: 2025-02-11 to 2025-11-17
  • LA GRANGE PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-08-09 to 2024-05-13
  • LANSINGNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-06-30 to 2026-03-04
  • LINCOLNWOODNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-07-11 to 2025-04-10
  • LYONSNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-03-06 to 2025-12-09
  • MARKHAMNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-03-19 to 2024-12-03
  • MATTESONNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-07-17 to 2025-04-01
  • MAYWOODNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-06-06 to 2025-03-25
  • MELROSE PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-09-21 to 2024-06-06
  • MIDLOTHIANNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-11-19 to 2025-08-05
  • MORTON GROVENot detected · below 9.0 µg/L lab reporting limitSample date: 2023-01-17 to 2023-10-23
  • MOUNT PROSPECTNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-11-16 to 2024-08-15
  • NILESNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-02-20 to 2025-11-21
  • NORTHBROOKNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-08-21 to 2024-08-12
  • OAK FORESTNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-11-30 to 2024-08-07
  • OAK LAWNNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-03-13 to 2024-12-11
  • OAK PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-01-21 to 2025-10-10
  • ORLAND PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-07-26 to 2024-04-05
  • PALATINENot detected · below 9.0 µg/L lab reporting limitSample date: 2023-04-10 to 2024-01-09
  • PALOS HEIGHTSNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-02-13 to 2024-11-05
  • PALOS HILLSNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-01-30 to 2023-10-17
  • PARK RIDGENot detected · below 9.0 µg/L lab reporting limitSample date: 2023-02-13 to 2023-11-13
  • RIVER FORESTNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-09-13 to 2024-06-06
  • RIVER GROVENot detected · below 9.0 µg/L lab reporting limitSample date: 2024-03-13 to 2024-12-10
  • RIVERDALENot detected · below 9.0 µg/L lab reporting limitSample date: 2024-12-10 to 2025-09-23
  • ROLLING MEADOWSNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-09-17 to 2025-06-16
  • SCHAUMBURGNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-05-16 to 2024-02-06
  • SCHILLER PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-03-22 to 2025-05-28
  • SKOKIENot detected · below 9.0 µg/L lab reporting limitSample date: 2025-03-10 to 2026-02-02
  • SOUTH HOLLANDNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-07-30 to 2025-04-03
  • STREAMWOODNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-03-18 to 2024-12-30
  • TINLEY PARKNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-05-11 to 2024-02-08
  • WESTCHESTERNot detected · below 9.0 µg/L lab reporting limitSample date: 2025-04-21 to 2026-01-26
  • WHEELINGNot detected · below 9.0 µg/L lab reporting limitSample date: 2023-11-14 to 2024-08-05
  • WILMETTENot detected · below 9.0 µg/L lab reporting limitSample date: 2024-06-17 to 2025-03-17
  • WINNETKANot detected · below 9.0 µg/L lab reporting limitSample date: 2025-01-13 to 2025-10-13
  • WORTHNot detected · below 9.0 µg/L lab reporting limitSample date: 2024-09-04 to 2025-06-04
Lead (90th percentile)Detected in 55 systems of 71 tested15 µg/L federal action level · US EPAHighest25 µg/L
  • LEMONT25 µg/LMonitoring period: 2026–2026 (still open)
  • MORTON GROVE17.4 µg/LMonitoring period: 2026–2026 (still open)
  • BARRINGTON13 µg/LMonitoring period: 2026–2026 (still open)
  • HOMEWOOD12.4 µg/LMonitoring period: 2026–2026 (still open)
  • CALUMET CITY11 µg/LMonitoring period: 2026–2026 (still open)
  • NORTHBROOK11 µg/LMonitoring period: 2026–2026 (still open)
  • BROOKFIELD10.4 µg/LMonitoring period: 2026–2026 (still open)
  • GLENVIEW10 µg/LMonitoring period: 2026–2026 (still open)
  • BLUE ISLAND9.95 µg/LMonitoring period: 2025–2025
  • NILES9.93 µg/LMonitoring period: 2026–2026 (still open)
  • SKOKIE9.77 µg/LMonitoring period: 2026–2026 (still open)
  • RIVER FOREST9.4 µg/LMonitoring period: 2026–2026 (still open)
  • OAK LAWN9.3 µg/LMonitoring period: 2026–2026 (still open)
  • PALATINE8.9 µg/LMonitoring period: 2026–2026 (still open)
  • MATTESON8.55 µg/LMonitoring period: 2026–2026 (still open)
  • LA GRANGE PARK8.5 µg/LMonitoring period: 2026–2026 (still open)
  • EVERGREEN PARK8.4 µg/LMonitoring period: 2026–2026 (still open)
  • MIDLOTHIAN8.37 µg/LMonitoring period: 2026–2026 (still open)
  • ARLINGTON HEIGHTS7.6 µg/LMonitoring period: 2026–2026 (still open)
  • WINNETKA7.6 µg/LMonitoring period: 2026–2026 (still open)
  • PARK RIDGE6.79 µg/LMonitoring period: 2026–2026 (still open)
  • FOREST PARK6.76 µg/LMonitoring period: 2026–2026 (still open)
  • EVANSTON6.5 µg/LMonitoring period: 2026–2026 (still open)
  • CHICAGO6.4 µg/LMonitoring period: 2026–2026 (still open)
  • HAZEL CREST6.4 µg/LMonitoring period: 2026–2026 (still open)
  • LYONS6.2 µg/LMonitoring period: 2026–2026 (still open)
  • RIVER GROVE6.09 µg/LMonitoring period: 2025–2025
  • WILMETTE6 µg/LMonitoring period: 2026–2026 (still open)
  • LA GRANGE5.99 µg/LMonitoring period: 2026–2026 (still open)
  • DES PLAINES5.7 µg/LMonitoring period: 2026–2026 (still open)
  • FRANKLIN PARK5.68 µg/LMonitoring period: 2025–2025
  • LANSING5.5 µg/LMonitoring period: 2026–2026 (still open)
  • CICERO5 µg/LMonitoring period: 2026–2026 (still open)
  • ELMWOOD PARK4.9 µg/LMonitoring period: 2026–2026 (still open)
  • RIVERDALE4.87 µg/LMonitoring period: 2026–2026 (still open)
  • MELROSE PARK4.7 µg/LMonitoring period: 2026–2026 (still open)
  • SOUTH HOLLAND4.6 µg/LMonitoring period: 2026–2026 (still open)
  • BELLWOOD4.53 µg/LMonitoring period: 2026–2026 (still open)
  • OAK PARK4.52 µg/LMonitoring period: 2026–2026 (still open)
  • LINCOLNWOOD3.69 µg/LMonitoring period: 2026–2026 (still open)
  • WESTERN SPRINGS3.6 µg/LMonitoring period: 2026–2026 (still open)
  • DOLTON2.77 µg/LMonitoring period: 2026–2026 (still open)
  • BERWYN2.35 µg/LMonitoring period: 2026–2026 (still open)
  • PARK FOREST2.3 µg/LMonitoring period: 2021–2023
  • MOUNT PROSPECT2.22 µg/LMonitoring period: 2026–2028 (still open)
  • HARVEY2.2 µg/LMonitoring period: 2021–2023
  • RICHTON PARK2.14 µg/LMonitoring period: 2026–2026 (still open)
  • SCHILLER PARK2.06 µg/LMonitoring period: 2026–2028 (still open)
  • ROLLING MEADOWS1.84 µg/LMonitoring period: 2024–2026 (still open)
  • CRESTWOOD1.6 µg/LMonitoring period: 2024–2026 (still open)
  • MARKHAM1.51 µg/LMonitoring period: 2025–2025
  • ALSIP1.21 µg/LMonitoring period: 2021–2023
  • WHEELING1.21 µg/LMonitoring period: 2024–2026 (still open)
  • WORTH1.2 µg/LMonitoring period: 2024–2026 (still open)
  • SCHAUMBURG0.87 µg/LMonitoring period: 2024–2026 (still open)
  • BRIDGEVIEWNot detectedMonitoring period: 2026–2028 (still open)
  • CHICAGO HEIGHTSNot detectedMonitoring period: 2025–2025
  • CHICAGO RIDGENot detectedMonitoring period: 2024–2026 (still open)
  • COUNTRY CLUB HILLSNot detectedMonitoring period: 2024–2026 (still open)
  • ELK GROVE VILLAGENot detectedMonitoring period: 2024–2026 (still open)
  • HICKORY HILLSNot detectedMonitoring period: 2021–2023
  • HOFFMAN ESTATESNot detectedMonitoring period: 2025–2025
  • JUSTICE-WILLOW SPRINGS WATER COMMISSIONNot detectedMonitoring period: 2025–2025
  • MAYWOODNot detectedMonitoring period: 2025–2025
  • OAK FORESTNot detectedMonitoring period: 2025–2025
  • ORLAND PARKNot detectedMonitoring period: 2025–2025
  • PALOS HEIGHTSNot detectedMonitoring period: 2024–2026 (still open)
  • PALOS HILLSNot detectedMonitoring period: 2025–2027 (still open)
  • STREAMWOODNot detectedMonitoring period: 2025–2025
  • TINLEY PARKNot detectedMonitoring period: 2026–2028 (still open)
  • WESTCHESTERNot detectedMonitoring period: 2025–2025
Perfluorooctanoic acid (PFOA)Detected in 1 system of 71 tested4.0 ng/L federal MCL (2024) · US EPAHighest4.3 ng/L
  • HOMEWOOD4.3 ng/LSample date: 2023-10-25 to 2024-06-05
  • ALSIPNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-07-10 to 2025-04-15
  • ARLINGTON HEIGHTSNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-12-12 to 2024-09-24
  • BARRINGTONNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-02-09 to 2023-08-15
  • BELLWOODNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-10-31 to 2026-02-05
  • BERWYNNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-11-21 to 2025-02-25
  • BLUE ISLANDNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-07-24 to 2024-11-05
  • BRIDGEVIEWNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-09-18 to 2024-06-20
  • BROOKFIELDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-02-12 to 2024-12-23
  • CALUMET CITYNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-08-08 to 2024-09-16
  • CHICAGONot detected · below 4.0 ng/L lab reporting limitSample date: 2024-01-08 to 2024-10-08
  • CHICAGO HEIGHTSNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-09-17 to 2025-06-03
  • CHICAGO RIDGENot detected · below 4.0 ng/L lab reporting limitSample date: 2024-07-17 to 2025-04-09
  • CICERONot detected · below 4.0 ng/L lab reporting limitSample date: 2023-01-25 to 2024-02-08
  • COUNTRY CLUB HILLSNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-12-05 to 2025-09-04
  • CRESTWOODNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-07-22 to 2026-04-22
  • DES PLAINESNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-05-06 to 2025-02-13
  • DOLTONNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-01-28 to 2026-01-28
  • ELK GROVE VILLAGENot detected · below 4.0 ng/L lab reporting limitSample date: 2024-11-19 to 2025-08-13
  • ELMWOOD PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-11-14 to 2025-09-10
  • EVANSTONNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-06-06 to 2024-03-07
  • EVERGREEN PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-06-21 to 2024-01-17
  • FOREST PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-04-11 to 2025-02-03
  • FRANKLIN PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-07-26 to 2024-04-09
  • GLENVIEWNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-11-07 to 2025-08-19
  • HARVEYNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-09-12 to 2024-06-11
  • HAZEL CRESTNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-10-10 to 2025-07-09
  • HICKORY HILLSNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-06-18 to 2025-03-18
  • HOFFMAN ESTATESNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-03-21 to 2023-12-05
  • JUSTICE-WILLOW SPRINGS WATER COMMISSIONNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-02-13 to 2025-11-20
  • LA GRANGENot detected · below 4.0 ng/L lab reporting limitSample date: 2025-02-11 to 2025-11-17
  • LA GRANGE PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-08-09 to 2024-06-20
  • LANSINGNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-06-30 to 2026-03-04
  • LEMONTNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-03-07 to 2024-10-10
  • LINCOLNWOODNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-07-11 to 2025-04-10
  • LYONSNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-03-06 to 2025-12-09
  • MARKHAMNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-03-19 to 2024-12-03
  • MATTESONNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-07-17 to 2025-04-01
  • MAYWOODNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-06-06 to 2025-03-25
  • MELROSE PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-10-25 to 2024-06-06
  • MIDLOTHIANNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-11-19 to 2025-08-05
  • MORTON GROVENot detected · below 4.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-10-23
  • MOUNT PROSPECTNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-11-16 to 2024-08-15
  • NILESNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-02-20 to 2025-11-21
  • NORTHBROOKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-08-21 to 2024-05-23
  • OAK FORESTNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-11-30 to 2024-08-07
  • OAK LAWNNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-03-13 to 2024-12-11
  • OAK PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-01-21 to 2025-10-10
  • ORLAND PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-08-11 to 2024-04-05
  • PALATINENot detected · below 4.0 ng/L lab reporting limitSample date: 2023-04-10 to 2024-01-09
  • PALOS HEIGHTSNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-02-13 to 2024-11-05
  • PALOS HILLSNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-01-30 to 2023-10-17
  • PARK FORESTNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-01-15 to 2025-07-16
  • PARK RIDGENot detected · below 4.0 ng/L lab reporting limitSample date: 2023-09-01 to 2023-11-13
  • RICHTON PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-02-13 to 2024-08-13
  • RIVER FORESTNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-09-13 to 2024-06-06
  • RIVER GROVENot detected · below 4.0 ng/L lab reporting limitSample date: 2024-03-13 to 2024-12-10
  • RIVERDALENot detected · below 4.0 ng/L lab reporting limitSample date: 2024-12-10 to 2025-09-23
  • ROLLING MEADOWSNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-09-17 to 2025-06-16
  • SCHAUMBURGNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-05-16 to 2024-02-06
  • SCHILLER PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-03-22 to 2025-05-28
  • SKOKIENot detected · below 4.0 ng/L lab reporting limitSample date: 2025-03-10 to 2025-12-08
  • SOUTH HOLLANDNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-07-30 to 2025-04-03
  • STREAMWOODNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-03-18 to 2024-12-30
  • TINLEY PARKNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-05-11 to 2024-02-08
  • WESTCHESTERNot detected · below 4.0 ng/L lab reporting limitSample date: 2025-04-21 to 2026-01-26
  • WESTERN SPRINGSNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-16
  • WHEELINGNot detected · below 4.0 ng/L lab reporting limitSample date: 2023-11-14 to 2024-08-19
  • WILMETTENot detected · below 4.0 ng/L lab reporting limitSample date: 2024-06-17 to 2025-03-17
  • WINNETKANot detected · below 4.0 ng/L lab reporting limitSample date: 2025-01-13 to 2025-10-13
  • WORTHNot detected · below 4.0 ng/L lab reporting limitSample date: 2024-09-04 to 2025-06-04
Water hardnessDetected in 1 systemAesthetic, no federal health limit · USGSHighest8.2 gpg
Total trihalomethanes (TTHM)Detected in 1 system80 ppb federal MCL · US EPAHighest26.4 ppb
  • CHICAGO26.4 ppbReporting year: 2025
Haloacetic acids (HAA5)Detected in 1 system60 ppb federal MCL · US EPAHighest13.8 ppb
  • CHICAGO13.8 ppbReporting year: 2025
Perfluorohexanoic acid (PFHxA)Detected in 2 systems of 71 tested400,000 ng/L Michigan EGLE state MCL (strictest US state) · Michigan EGLEHighest3 ng/L
  • CALUMET CITY3 ng/LSample date: 2023-08-08 to 2024-09-16
  • MARKHAM3 ng/LSample date: 2024-03-19 to 2024-12-03
  • ALSIPNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-10 to 2025-04-15
  • ARLINGTON HEIGHTSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-12-12 to 2024-09-24
  • BARRINGTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-09 to 2023-08-15
  • BELLWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-10-31 to 2026-02-05
  • BERWYNNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-21 to 2025-02-25
  • BLUE ISLANDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-07-24 to 2024-11-05
  • BRIDGEVIEWNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-18 to 2024-06-20
  • BROOKFIELDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-02-12 to 2024-12-23
  • CHICAGONot detected · below 3.0 ng/L lab reporting limitSample date: 2024-01-08 to 2024-10-08
  • CHICAGO HEIGHTSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-09-17 to 2025-06-03
  • CHICAGO RIDGENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-17 to 2025-04-09
  • CICERONot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-25 to 2024-02-08
  • COUNTRY CLUB HILLSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-12-05 to 2025-09-04
  • CRESTWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-07-22 to 2026-04-22
  • DES PLAINESNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-06 to 2025-02-13
  • DOLTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-28 to 2026-01-28
  • ELK GROVE VILLAGENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-19 to 2025-08-13
  • ELMWOOD PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-14 to 2025-09-10
  • EVANSTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-06-06 to 2024-03-07
  • EVERGREEN PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-06-21 to 2024-01-17
  • FOREST PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-04-11 to 2025-02-03
  • FRANKLIN PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-07-26 to 2024-04-09
  • GLENVIEWNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-07 to 2025-08-19
  • HARVEYNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-12 to 2024-06-11
  • HAZEL CRESTNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-10-10 to 2025-07-09
  • HICKORY HILLSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-06-18 to 2025-03-18
  • HOFFMAN ESTATESNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-21 to 2023-12-05
  • HOMEWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-25 to 2024-06-05
  • JUSTICE-WILLOW SPRINGS WATER COMMISSIONNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-13 to 2025-11-20
  • LA GRANGENot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-11 to 2025-11-17
  • LA GRANGE PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-09 to 2024-06-20
  • LANSINGNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-06-30 to 2026-03-04
  • LEMONTNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-07 to 2024-10-10
  • LINCOLNWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-11 to 2025-04-10
  • LYONSNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-06 to 2025-12-09
  • MATTESONNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-17 to 2025-04-01
  • MAYWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-06-06 to 2025-03-25
  • MELROSE PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-25 to 2024-06-06
  • MIDLOTHIANNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-19 to 2025-08-05
  • MORTON GROVENot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-10-23
  • MOUNT PROSPECTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-11-16 to 2024-08-15
  • NILESNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-20 to 2025-11-21
  • NORTHBROOKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-21 to 2024-05-23
  • OAK FORESTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-11-30 to 2024-08-07
  • OAK LAWNNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-13 to 2024-12-11
  • OAK PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-21 to 2025-10-10
  • ORLAND PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-11 to 2024-04-05
  • PALATINENot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-10 to 2024-01-09
  • PALOS HEIGHTSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-02-13 to 2024-11-05
  • PALOS HILLSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-30 to 2023-10-17
  • PARK FORESTNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-15 to 2025-07-16
  • PARK RIDGENot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-01 to 2023-11-13
  • RICHTON PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-02-13 to 2024-08-13
  • RIVER FORESTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-13 to 2024-06-06
  • RIVER GROVENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-13 to 2024-12-10
  • RIVERDALENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-12-10 to 2025-09-23
  • ROLLING MEADOWSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-09-17 to 2025-06-16
  • SCHAUMBURGNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-05-16 to 2024-02-06
  • SCHILLER PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-22 to 2025-05-28
  • SKOKIENot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-10 to 2025-12-08
  • SOUTH HOLLANDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-30 to 2025-04-03
  • STREAMWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-18 to 2024-12-30
  • TINLEY PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-05-11 to 2024-02-08
  • WESTCHESTERNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-04-21 to 2026-01-26
  • WESTERN SPRINGSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-16
  • WHEELINGNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-11-14 to 2024-08-19
  • WILMETTENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-06-17 to 2025-03-17
  • WINNETKANot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-13 to 2025-10-13
  • WORTHNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-09-04 to 2025-06-04
Perfluorobutanoic acid (PFBA)Detected in 2 systems of 71 testedNo federal or state limit; shown for transparencyHighest9.3 ng/L
  • OAK FOREST9.3 ng/LSample date: 2023-11-30 to 2024-08-07
  • SOUTH HOLLAND7.3 ng/LSample date: 2024-07-30 to 2025-04-03
  • ALSIPNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-07-10 to 2025-04-15
  • ARLINGTON HEIGHTSNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-12-12 to 2024-09-24
  • BARRINGTONNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-02-09 to 2023-08-15
  • BELLWOODNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-10-31 to 2026-02-05
  • BERWYNNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-11-21 to 2025-02-25
  • BLUE ISLANDNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-24 to 2024-11-05
  • BRIDGEVIEWNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-09-18 to 2024-06-20
  • BROOKFIELDNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-02-12 to 2024-12-23
  • CALUMET CITYNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-08-08 to 2024-09-16
  • CHICAGONot detected · below 5.0 ng/L lab reporting limitSample date: 2024-01-08 to 2024-10-08
  • CHICAGO HEIGHTSNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-09-17 to 2025-06-03
  • CHICAGO RIDGENot detected · below 5.0 ng/L lab reporting limitSample date: 2024-07-17 to 2025-04-09
  • CICERONot detected · below 5.0 ng/L lab reporting limitSample date: 2023-01-25 to 2024-02-08
  • COUNTRY CLUB HILLSNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-12-05 to 2025-09-04
  • CRESTWOODNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-07-22 to 2026-04-22
  • DES PLAINESNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-05-06 to 2025-02-13
  • DOLTONNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-01-28 to 2026-01-28
  • ELK GROVE VILLAGENot detected · below 5.0 ng/L lab reporting limitSample date: 2024-11-19 to 2025-08-13
  • ELMWOOD PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-11-14 to 2025-09-10
  • EVANSTONNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-06-06 to 2024-03-07
  • EVERGREEN PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-06-21 to 2024-01-17
  • FOREST PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-04-11 to 2025-02-03
  • FRANKLIN PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-07-26 to 2024-04-09
  • GLENVIEWNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-11-07 to 2025-08-19
  • HARVEYNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-09-12 to 2024-06-11
  • HAZEL CRESTNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-10-10 to 2025-07-09
  • HICKORY HILLSNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-06-18 to 2025-03-18
  • HOFFMAN ESTATESNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-03-21 to 2023-12-05
  • HOMEWOODNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-10-25 to 2024-06-05
  • JUSTICE-WILLOW SPRINGS WATER COMMISSIONNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-02-13 to 2025-11-20
  • LA GRANGENot detected · below 5.0 ng/L lab reporting limitSample date: 2025-02-11 to 2025-11-17
  • LA GRANGE PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-08-09 to 2024-06-20
  • LANSINGNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-06-30 to 2026-03-04
  • LEMONTNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-03-07 to 2024-10-10
  • LINCOLNWOODNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-07-11 to 2025-04-10
  • LYONSNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-03-06 to 2025-12-09
  • MARKHAMNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-03-19 to 2024-12-03
  • MATTESONNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-07-17 to 2025-04-01
  • MAYWOODNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-06-06 to 2025-03-25
  • MELROSE PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-10-25 to 2024-06-06
  • MIDLOTHIANNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-11-19 to 2025-08-05
  • MORTON GROVENot detected · below 5.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-10-23
  • MOUNT PROSPECTNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-11-16 to 2024-08-15
  • NILESNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-02-20 to 2025-11-21
  • NORTHBROOKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-08-21 to 2024-05-23
  • OAK LAWNNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-03-13 to 2024-12-11
  • OAK PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-01-21 to 2025-10-10
  • ORLAND PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-08-11 to 2024-04-05
  • PALATINENot detected · below 5.0 ng/L lab reporting limitSample date: 2023-04-10 to 2024-01-09
  • PALOS HEIGHTSNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-02-13 to 2024-11-05
  • PALOS HILLSNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-01-30 to 2023-10-17
  • PARK FORESTNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-01-15 to 2025-07-16
  • PARK RIDGENot detected · below 5.0 ng/L lab reporting limitSample date: 2023-09-01 to 2023-11-13
  • RICHTON PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-02-13 to 2024-08-13
  • RIVER FORESTNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-09-13 to 2024-06-06
  • RIVER GROVENot detected · below 5.0 ng/L lab reporting limitSample date: 2024-03-13 to 2024-12-10
  • RIVERDALENot detected · below 5.0 ng/L lab reporting limitSample date: 2024-12-10 to 2025-09-23
  • ROLLING MEADOWSNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-09-17 to 2025-06-16
  • SCHAUMBURGNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-05-16 to 2024-02-06
  • SCHILLER PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-03-22 to 2025-05-28
  • SKOKIENot detected · below 5.0 ng/L lab reporting limitSample date: 2025-03-10 to 2025-12-08
  • STREAMWOODNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-03-18 to 2024-12-30
  • TINLEY PARKNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-05-11 to 2024-02-08
  • WESTCHESTERNot detected · below 5.0 ng/L lab reporting limitSample date: 2025-04-21 to 2026-01-26
  • WESTERN SPRINGSNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-16
  • WHEELINGNot detected · below 5.0 ng/L lab reporting limitSample date: 2023-11-14 to 2024-08-19
  • WILMETTENot detected · below 5.0 ng/L lab reporting limitSample date: 2024-06-17 to 2025-03-17
  • WINNETKANot detected · below 5.0 ng/L lab reporting limitSample date: 2025-01-13 to 2025-10-13
  • WORTHNot detected · below 5.0 ng/L lab reporting limitSample date: 2024-09-04 to 2025-06-04
1 more contaminant detectedShow
Perfluoropentanoic acid (PFPeA)Detected in 1 system of 71 testedNo federal or state limit; shown for transparencyHighest3.2 ng/L
  • CALUMET CITY3.2 ng/LSample date: 2023-08-08 to 2024-09-16
  • ALSIPNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-10 to 2025-04-15
  • ARLINGTON HEIGHTSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-12-12 to 2024-09-24
  • BARRINGTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-02-09 to 2023-08-15
  • BELLWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-10-31 to 2026-02-05
  • BERWYNNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-21 to 2025-02-25
  • BLUE ISLANDNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-07-24 to 2024-11-05
  • BRIDGEVIEWNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-18 to 2024-06-20
  • BROOKFIELDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-02-12 to 2024-12-23
  • CHICAGONot detected · below 3.0 ng/L lab reporting limitSample date: 2024-01-08 to 2024-10-08
  • CHICAGO HEIGHTSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-09-17 to 2025-06-03
  • CHICAGO RIDGENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-17 to 2025-04-09
  • CICERONot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-25 to 2024-02-08
  • COUNTRY CLUB HILLSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-12-05 to 2025-09-04
  • CRESTWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-07-22 to 2026-04-22
  • DES PLAINESNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-05-06 to 2025-02-13
  • DOLTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-28 to 2026-01-28
  • ELK GROVE VILLAGENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-19 to 2025-08-13
  • ELMWOOD PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-14 to 2025-09-10
  • EVANSTONNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-06-06 to 2024-03-07
  • EVERGREEN PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-06-21 to 2024-01-17
  • FOREST PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-04-11 to 2025-02-03
  • FRANKLIN PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-07-26 to 2024-04-09
  • GLENVIEWNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-07 to 2025-08-19
  • HARVEYNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-12 to 2024-06-11
  • HAZEL CRESTNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-10-10 to 2025-07-09
  • HICKORY HILLSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-06-18 to 2025-03-18
  • HOFFMAN ESTATESNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-21 to 2023-12-05
  • HOMEWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-25 to 2024-06-05
  • JUSTICE-WILLOW SPRINGS WATER COMMISSIONNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-13 to 2025-11-20
  • LA GRANGENot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-11 to 2025-11-17
  • LA GRANGE PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-09 to 2024-06-20
  • LANSINGNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-06-30 to 2026-03-04
  • LEMONTNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-07 to 2024-10-10
  • LINCOLNWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-11 to 2025-04-10
  • LYONSNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-06 to 2025-12-09
  • MARKHAMNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-19 to 2024-12-03
  • MATTESONNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-17 to 2025-04-01
  • MAYWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-06-06 to 2025-03-25
  • MELROSE PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-25 to 2024-06-06
  • MIDLOTHIANNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-11-19 to 2025-08-05
  • MORTON GROVENot detected · below 3.0 ng/L lab reporting limitSample date: 2023-03-28 to 2023-10-23
  • MOUNT PROSPECTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-11-16 to 2024-08-15
  • NILESNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-02-20 to 2025-11-21
  • NORTHBROOKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-21 to 2024-05-23
  • OAK FORESTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-11-30 to 2024-08-07
  • OAK LAWNNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-13 to 2024-12-11
  • OAK PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-21 to 2025-10-10
  • ORLAND PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-08-11 to 2024-04-05
  • PALATINENot detected · below 3.0 ng/L lab reporting limitSample date: 2023-04-10 to 2024-01-09
  • PALOS HEIGHTSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-02-13 to 2024-11-05
  • PALOS HILLSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-01-30 to 2023-10-17
  • PARK FORESTNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-15 to 2025-07-16
  • PARK RIDGENot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-01 to 2023-11-13
  • RICHTON PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-02-13 to 2024-08-13
  • RIVER FORESTNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-09-13 to 2024-06-06
  • RIVER GROVENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-13 to 2024-12-10
  • RIVERDALENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-12-10 to 2025-09-23
  • ROLLING MEADOWSNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-09-17 to 2025-06-16
  • SCHAUMBURGNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-05-16 to 2024-02-06
  • SCHILLER PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-22 to 2025-05-28
  • SKOKIENot detected · below 3.0 ng/L lab reporting limitSample date: 2025-03-10 to 2025-12-08
  • SOUTH HOLLANDNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-07-30 to 2025-04-03
  • STREAMWOODNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-03-18 to 2024-12-30
  • TINLEY PARKNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-05-11 to 2024-02-08
  • WESTCHESTERNot detected · below 3.0 ng/L lab reporting limitSample date: 2025-04-21 to 2026-01-26
  • WESTERN SPRINGSNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-10-11 to 2024-04-16
  • WHEELINGNot detected · below 3.0 ng/L lab reporting limitSample date: 2023-11-14 to 2024-08-19
  • WILMETTENot detected · below 3.0 ng/L lab reporting limitSample date: 2024-06-17 to 2025-03-17
  • WINNETKANot detected · below 3.0 ng/L lab reporting limitSample date: 2025-01-13 to 2025-10-13
  • WORTHNot detected · below 3.0 ng/L lab reporting limitSample date: 2024-09-04 to 2025-06-04
25 PFAS tested, none detected in any systemShow

Tested in these 71 systems: ALSIP, ARLINGTON HEIGHTS, BARRINGTON, BELLWOOD, BERWYN, BLUE ISLAND, BRIDGEVIEW, BROOKFIELD, CALUMET CITY, CHICAGO, CHICAGO HEIGHTS, CHICAGO RIDGE, CICERO, COUNTRY CLUB HILLS, CRESTWOOD, DES PLAINES, DOLTON, ELK GROVE VILLAGE, ELMWOOD PARK, EVANSTON, EVERGREEN PARK, FOREST PARK, FRANKLIN PARK, GLENVIEW, HARVEY, HAZEL CREST, HICKORY HILLS, HOFFMAN ESTATES, HOMEWOOD, JUSTICE-WILLOW SPRINGS WATER COMMISSION, LA GRANGE, LA GRANGE PARK, LANSING, LEMONT, LINCOLNWOOD, LYONS, MARKHAM, MATTESON, MAYWOOD, MELROSE PARK, MIDLOTHIAN, MORTON GROVE, MOUNT PROSPECT, NILES, NORTHBROOK, OAK FOREST, OAK LAWN, OAK PARK, ORLAND PARK, PALATINE, PALOS HEIGHTS, PALOS HILLS, PARK FOREST, PARK RIDGE, RICHTON PARK, RIVER FOREST, RIVER GROVE, RIVERDALE, ROLLING MEADOWS, SCHAUMBURG, SCHILLER PARK, SKOKIE, SOUTH HOLLAND, STREAMWOOD, TINLEY PARK, WESTCHESTER, WESTERN SPRINGS, WHEELING, WILMETTE, WINNETKA, WORTH

  • 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS)
  • 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS)
  • 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS)
  • 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS)
  • 4,8-Dioxa-3H-perfluorononanoic acid (ADONA)
  • 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS)
  • Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals)
  • N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA)
  • N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA)
  • Nonafluoro-3,6-dioxaheptanoic acid (NFDHA)
  • Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA)
  • Perfluoro-3-methoxypropanoic acid (PFMPA)
  • Perfluoro-4-methoxybutanoic acid (PFMBA)
  • Perfluorobutanesulfonic acid (PFBS)
  • Perfluorodecanoic acid (PFDA)
  • Perfluorododecanoic acid (PFDoA)
  • Perfluoroheptanesulfonic acid (PFHpS)
  • Perfluoroheptanoic acid (PFHpA)
  • Perfluorohexanesulfonic acid (PFHxS)
  • Perfluorononanoic acid (PFNA)
  • Perfluorooctanesulfonic acid (PFOS)
  • Perfluoropentanesulfonic acid (PFPeS)
  • Perfluorotetradecanoic acid (PFTA)
  • Perfluorotridecanoic acid (PFTrDA)
  • Perfluoroundecanoic acid (PFUnA)
71 cities

Cities ranked by the records

Showing 6 of 71 cities · scores are system-level, not tap tests

Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no county score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works.

PFAS in Cook County1 of 71 city reports had a PFAS sample above a 2024 EPA limit
4.0 ng/L federal MCL · PFOS, ng/LPFAS in Illinois
Lead

2of 71 cities above the 15 µg/L action level

Based on each system's 90th-percentile result. Lead from household plumbing isn't in this record.

Lead in Illinois
Hard water

1city reports hardness · Chicago, 8.2 gpg

Hard on the USGS scale. An aesthetic measure with no federal health limit.

Hard water explained
Who supplies the county

Largest water systems

  1. ChicagoCHICAGO · IL0316000
    2,721,308 served
  2. CiceroCICERO · IL0310510
    83,000 served
  3. SchaumburgSCHAUMBURG · IL0314890
    75,750 served
  4. EvanstonEVANSTON · IL0310810
    74,486 served
  5. Arlington HeightsARLINGTON HEIGHTS · IL0314030
    73,320 served
  6. PalatinePALATINE · IL0312340
    70,875 served
  7. SkokieSKOKIE · IL0312880
    66,422 served
  8. Des PlainesDES PLAINES · IL0310630
    60,675 served
  9. Oak LawnOAK LAWN · IL0312220
    58,362 served
  10. Orland ParkORLAND PARK · IL0312310
    58,020 served
Questions

Frequently asked

How does Cook County tap water compare across cities?

PurityMap ranks 71 cities in Cook County by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Orland Park's main water system: ORLAND PARK · PWSID IL0312310 · Purity Score 100 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.

How many Cook County cities had a PFAS sample above a 2024 EPA limit?

1 of 71 Cook County city reports had a PFAS sample above a 2024 EPA limit in EPA's UCMR 5 testing, including Homewood (PFOA 4.3 ng/L). That limit is judged on a yearly average, and water systems have until 2029 to meet it, so a single sample is not a violation. PFAS were detected at any level in 5.

Is there lead in Cook County tap water?

Utilities report lead as a 90th-percentile result from home taps. 55 of 71 Cook County cities reported a value above zero, and 2 cities were above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.

Have Cook County water systems had drinking-water violations?

4 cities in Cook County have a health-based violation in the federal SDWIS record within about the last ten years. Each city report lists the contaminant, year and whether it was resolved.

Does Cook County have hard water?

Hardness is published in utility water-quality reports for 1 Cook County city on record; the hardest is Chicago at 8.2 grains per gallon. Hardness affects scale and appliances; it is not a health finding.

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