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Johnson County, IL Water Quality

Water quality data for 5 public water systems serving Johnson County, Illinois — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 5 water systems · 6 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

Johnson County Earns a B

Johnson County: 6 communities across 5 water systems. 100.0% have no open violations.

  • Median lead where detected: 5.50 ppb
  • 1 communities with a lead detection, 5 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 5 with significant inspection deficiencies
  • 100.0% of communities have no open violations
5.5 ppb
Median Lead Level
County-wide, 90th percentile
5
Water Systems
Active CWS & NTNCWS
100%
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
  • Vienna
    Not detected
    2 health-based violations since 2015
    B
  • Cypress
    Not detected
    4 significant inspection deficiencies
    B
  • Belknap
    Not detected
    4 significant inspection deficiencies
    B
  • Goreville
    Not detected
    3 significant inspection deficiencies
    C
  • Buncombe
    Not detected
    3 significant inspection deficiencies
    C
⚠ Needs Attention
  • Buncombe
    Not detected
    3 significant inspection deficiencies
    C
  • New Burnside
    5.50 ppb
    3 significant inspection deficiencies
    C
  • Goreville
    Not detected
    3 significant inspection deficiencies
    C
  • Cypress
    Not detected
    4 significant inspection deficiencies
    B
  • Belknap
    Not detected
    4 significant inspection deficiencies
    B
County Lead Level — Median 5.5 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 5.5 ppb — 36.7% of the federal action level
Systems by Lead Level
5 – 10 ppb
1
No Data
5

All Cities in Johnson County

Vienna Not detected B
Goreville Not detected C
Buncombe Not detected C
Cypress Not detected B
New Burnside 5.50 ppb C
Belknap Not detected B
Showing 6 cities
No active violations Active violations

About Johnson County Drinking Water

Johnson County is served by 5 water systems covering 6 communities. No community here has an open violation on record.

Of the communities reporting lead results, 1 recorded a detection, with a median of 5.50 ppb — 37% of the federal action level. 5 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 5 of them.

Frequently Asked Questions

Is Johnson County tap water safe to drink?▼
No community in Johnson County has an open violation on record. No community has PFAS above the federal limit on record.
What is the lead level in Johnson County?▼
Among communities with a detection the median is 5.50 ppb, 37% of the 15 ppb action level. 5 reported none detected and 0 reported no result.
How many water systems serve Johnson County?▼
5 community water systems serve 6 communities here.
← Back to Illinois water quality overview