States › Illinois › Williamson County

Williamson County, IL Water Quality

Water quality data for 12 public water systems serving Williamson County, Illinois — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 12 water systems · 17 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

Williamson County Earns a B

Williamson County: 17 communities across 12 water systems. 82.4% have no open violations.

  • Median lead where detected: 7.68 ppb
  • 6 communities with a lead detection, 11 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 12 with significant inspection deficiencies
  • 82.4% of communities have no open violations
7.68 ppb
Median Lead Level
County-wide, 90th percentile
12
Water Systems
Active CWS & NTNCWS
82%
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
  • Marion
    Not detected
    No federal limits exceeded on record
    A
  • Pittsburg
    Not detected
    No federal limits exceeded on record
    B
  • Spillertown
    Not detected
    No federal limits exceeded on record
    A
  • Cambria
    Not detected
    1 significant inspection deficiency
    B
  • Crab Orchard
    Not detected
    1 significant inspection deficiency
    A
⚠ Needs Attention
  • Hurst
    Not detected
    1 violation currently open
    D
  • Bush
    Not detected
    1 violation currently open
    D
  • Colp
    Not detected
    1 violation currently open
    D
  • Blairsville
    Not detected
    3 significant inspection deficiencies
    C
  • Carterville
    7.54 ppb
    3 significant inspection deficiencies
    C
County Lead Level — Median 7.68 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 7.68 ppb — 51.2% of the federal action level
Systems by Lead Level
5 – 10 ppb
4
10 – 15 ppb
2
No Data
11

All Cities in Williamson County

Marion Not detected A
Herrin 10.00 ppb B
Carterville 7.54 ppb C
Johnston City 7.68 ppb B
Cambria Not detected B
Energy 10.00 ppb B
Crainville 7.54 ppb C
Creal Springs Not detected C
Pittsburg Not detected B
Hurst Not detected D
Crab Orchard Not detected A
Spillertown Not detected A
Bush Not detected D
Colp Not detected D
Blairsville Not detected C
Stonefort Not detected B
Whiteash 7.68 ppb B
Showing 17 cities
No active violations Active violations

About Williamson County Drinking Water

Williamson County is served by 12 water systems covering 17 communities. 82% have no open violations.

Of the communities reporting lead results, 6 recorded a detection, with a median of 7.68 ppb — 51% of the federal action level. 11 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 12 of them.

Frequently Asked Questions

Is Williamson County tap water safe to drink?▼
82% of communities have no open violation. No community has PFAS above the federal limit on record.
What is the lead level in Williamson County?▼
Among communities with a detection the median is 7.68 ppb, 51% of the 15 ppb action level. 11 reported none detected and 0 reported no result.
How many water systems serve Williamson County?▼
12 community water systems serve 17 communities here.
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