States › Illinois › Mason County

Mason County, IL Water Quality

Water quality data for 6 public water systems serving Mason County, Illinois — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 6 water systems · 6 cities
✅
Excellent — All Systems Performing Well

Water quality across the county is outstanding with minimal violations and very low lead levels.

A

Mason County Earns a A

Mason County: 6 communities across 6 water systems. 83.3% have no open violations.

  • Median lead where detected: 3.80 ppb
  • 3 communities with a lead detection, 3 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 2 with significant inspection deficiencies
  • 83.3% of communities have no open violations
3.8 ppb
Median Lead Level
County-wide, 90th percentile
6
Water Systems
Active CWS & NTNCWS
83%
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
  • Manito
    Not detected
    No federal limits exceeded on record
    B
  • San Jose
    3.80 ppb
    No federal limits exceeded on record
    B
  • Easton
    Not detected
    1 health-based violation since 2015
    B
  • Havana
    4.60 ppb
    2 significant inspection deficiencies
    A
  • Mason City
    Not detected
    1 significant inspection deficiency
    B
⚠ Needs Attention
  • Forest City
    2.10 ppb
    1 violation currently open
    C
  • Havana
    4.60 ppb
    2 significant inspection deficiencies
    A
  • Mason City
    Not detected
    1 significant inspection deficiency
    B
  • Easton
    Not detected
    1 health-based violation since 2015
    B
  • Manito
    Not detected
    No federal limits exceeded on record
    B
County Lead Level — Median 3.8 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 3.8 ppb — 25.3% of the federal action level
Systems by Lead Level
Under 5 ppb
3
No Data
3

All Cities in Mason County

Havana 4.60 ppb A
Mason City Not detected B
Manito Not detected B
San Jose 3.80 ppb B
Easton Not detected B
Forest City 2.10 ppb C
Showing 6 cities
No active violations Active violations

About Mason County Drinking Water

Mason County is served by 6 water systems covering 6 communities. 83% have no open violations.

Of the communities reporting lead results, 3 recorded a detection, with a median of 3.80 ppb — 25% of the federal action level. 3 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 2 of them.

Frequently Asked Questions

Is Mason County tap water safe to drink?▼
83% of communities have no open violation. No community has PFAS above the federal limit on record.
What is the lead level in Mason County?▼
Among communities with a detection the median is 3.80 ppb, 25% of the 15 ppb action level. 3 reported none detected and 0 reported no result.
How many water systems serve Mason County?▼
6 community water systems serve 6 communities here.
← Back to Illinois water quality overview