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Cook County, IL Water Quality

Water quality data for 109 public water systems serving Cook County, Illinois — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 109 water systems · 119 cities
✅
Generally Safe — Most Systems Performing Well

The majority of water systems have no active violations and lead levels well below the federal action level.

B

Cook County Earns a B

Cook County: 119 communities across 109 water systems. 96.6% have no open violations.

  • Median lead where detected: 5.47 ppb
  • 84 communities with a lead detection, 35 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 102 with significant inspection deficiencies
  • 96.6% of communities have no open violations
5.47 ppb
Median Lead Level
County-wide, 90th percentile
109
Water Systems
Active CWS & NTNCWS
96%
Violation-Free
No active violations on record
How we grade counties: MyWaterIQ uses EPA SDWIS enforcement data — actual MCL violations and lead test results — not the aspirational MCLG targets used by some sites. A grade reflects real compliance history, not theoretical risk. Learn more →

Cities by Water Quality

⭐ Best Performing
  • Glenview
    Not detected
    No federal limits exceeded on record
    A
  • Streamwood
    2.31 ppb
    No federal limits exceeded on record
    A
  • Elk Grove Village
    Not detected
    No federal limits exceeded on record
    A
  • Chicago Ridge
    Not detected
    No federal limits exceeded on record
    A
  • Justice
    Not detected
    No federal limits exceeded on record
    A
⚠ Needs Attention
  • Calumet City
    12.40 ppb
    1 violation currently open
    D
  • Maywood
    1.20 ppb
    1 violation currently open
    D
  • Lemont
    20.00 ppb
    Lead above the 15 ppb action level
    D
  • Morton Grove
    17.60 ppb
    Lead above the 15 ppb action level
    D
  • Burbank
    0.70 ppb
    1 violation currently open
    D
County Lead Level — Median 5.47 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 5.47 ppb — 36.5% of the federal action level
Systems by Lead Level
Under 5 ppb
38
5 – 10 ppb
38
10 – 15 ppb
8
No Data
35

All Cities in Cook County

Chicago 7.00 ppb B
Cicero 5.00 ppb C
Evanston 1.90 ppb A
Schaumburg 1.35 ppb A
Arlington Heights 8.83 ppb B
Skokie 7.99 ppb B
Palatine 7.50 ppb B
Oak Lawn 8.10 ppb B
Orland Park Not detected B
Des Plaines 11.10 ppb B
Berwyn 1.80 ppb C
Tinley Park Not detected A
Oak Park 5.08 ppb B
Hoffman Estates 1.40 ppb A
Glenview Not detected A
Mount Prospect 4.27 ppb A
Streamwood 2.31 ppb A
Park Ridge 6.79 ppb B
Hanover Park 1.46 ppb A
Wheeling 1.29 ppb B
Northbrook 11.00 ppb A
Calumet City 12.40 ppb D
Elk Grove Village Not detected A
Burbank 0.70 ppb D
Lansing 5.50 ppb C
Niles 9.93 ppb B
Wilmette 9.90 ppb A
Chicago Heights Not detected B
Oak Forest Not detected B
Morton Grove 17.60 ppb D
Elmwood Park 3.04 ppb B
Rolling Meadows 0.93 ppb A
Melrose Park 5.58 ppb C
Blue Island 9.95 ppb C
South Holland 0.70 ppb B
Maywood 1.20 ppb D
Harvey 2.20 ppb B
Park Forest 2.30 ppb B
Evergreen Park 6.34 ppb B
Homewood 14.00 ppb C
Bellwood Not detected B
Brookfield 7.63 ppb C
Matteson 8.56 ppb C
Palos Hills 0.75 ppb B
Alsip 1.21 ppb A
Franklin Park Not detected A
Dolton 2.77 ppb B
Westchester 9.00 ppb B
Lemont 20.00 ppb D
Country Club Hills Not detected B
Norridge Not detected B
Bridgeview Not detected A
Hickory Hills Not detected A
Chicago Ridge Not detected A
Midlothian 7.28 ppb B
Forest Park 4.00 ppb B
Lincolnwood Not detected A
Hazel Crest 5.30 ppb A
Western Springs 2.04 ppb C
La Grange Not detected B
La Grange Park 6.90 ppb C
Winnetka 8.50 ppb A
Northlake 3.95 ppb A
Justice Not detected A
Richton Park 7.40 ppb C
Palos Heights Not detected A
Schiller Park 1.54 ppb A
Markham 1.51 ppb A
River Forest 6.09 ppb C
Summit 8.00 ppb B
Worth Not detected A
Crestwood 2.10 ppb B
Riverdale 4.82 ppb B
Lyons 1.10 ppb A
Sauk Village Not detected B
Harwood Heights 6.57 ppb B
Glencoe 6.90 ppb A
Barrington 9.20 ppb B
Prospect Heights Not detected A
Flossmoor 5.43 ppb C
Riverside 7.40 ppb C
Glenwood Not detected A
Broadview 5.88 ppb B
Hillside 0.90 ppb A
North Riverside 8.60 ppb B
Calumet Park 6.00 ppb B
Lynwood 0.59 ppb A
Orland Hills Not detected B
Posen 3.62 ppb A
Northfield 1.40 ppb A
Robbins Not detected A
Olympia Fields 4.18 ppb A
Hometown Not detected B
Berkeley 0.70 ppb A
South Chicago Heights Not detected B
Burnham 14.20 ppb B
Indian Head Park Not detected B
Stickney 3.29 ppb B
Countryside Not detected A
Willow Springs Not detected A
Dixmoor 2.71 ppb B
South Barrington Not detected B
Kenilworth 6.50 ppb B
Thornton 2.80 ppb B
Palos Park Not detected A
Rosemont Not detected B
Stone Park 3.95 ppb A
Phoenix 6.75 ppb B
Merrionette Park Not detected B
Inverness 9.20 ppb B
Hodgkins Not detected A
Forest View 6.20 ppb B
East Hazel Crest 14.00 ppb C
Golf 9.30 ppb B
McCook 1.10 ppb A
Barrington Hills 9.20 ppb B
River Grove Not detected A
Bedford Park 0.70 ppb D
Ford Heights Not detected B
Showing 119 cities
No active violations Active violations

About Cook County Drinking Water

Cook County is served by 109 water systems covering 119 communities. 97% have no open violations.

Of the communities reporting lead results, 84 recorded a detection, with a median of 5.47 ppb — 36% of the federal action level. 35 reported none detected, which means below the laboratory limit rather than an absence of lead.

No community here has PFAS above the federal limit on record. State inspectors recorded significant deficiencies at 102 of them.

Frequently Asked Questions

Is Cook County tap water safe to drink?▼
97% of communities have no open violation. No community has PFAS above the federal limit on record.
What is the lead level in Cook County?▼
Among communities with a detection the median is 5.47 ppb, 36% of the 15 ppb action level. 35 reported none detected and 0 reported no result.
How many water systems serve Cook County?▼
109 community water systems serve 119 communities here.
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