States › Illinois › LaSalle County

LaSalle County, IL Water Quality

Water quality data for 21 public water systems serving LaSalle County, Illinois — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 21 water systems · 26 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

LaSalle County Earns a B

LaSalle County: 26 communities across 21 water systems. 92.3% have no open violations.

  • Median lead where detected: 2.06 ppb
  • 16 communities with a lead detection, 10 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 16 with significant inspection deficiencies
  • 92.3% of communities have no open violations
2.06 ppb
Median Lead Level
County-wide, 90th percentile
21
Water Systems
Active CWS & NTNCWS
92%
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
  • Seneca
    Not detected
    No federal limits exceeded on record
    B
  • Earlville
    2.90 ppb
    No federal limits exceeded on record
    B
  • Tonica
    Not detected
    No federal limits exceeded on record
    B
  • Rutland
    Not detected
    No federal limits exceeded on record
    B
  • Grand Ridge
    Not detected
    2 health-based violations since 2015
    B
⚠ Needs Attention
  • Marseilles
    19.10 ppb
    Lead above the 15 ppb action level
    F
  • Lostant
    0.65 ppb
    1 violation currently open
    D
  • Mendota
    8.07 ppb
    1 significant inspection deficiency
    C
  • North Utica
    5.31 ppb
    3 significant inspection deficiencies
    C
  • Oglesby
    Not detected
    Copper above the 1,300 ppb action level
    C
County Lead Level — Median 2.06 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 2.06 ppb — 13.7% of the federal action level
Systems by Lead Level
Under 5 ppb
11
5 – 10 ppb
3
10 – 15 ppb
2
No Data
10

All Cities in LaSalle County

Ottawa 2.06 ppb C
Streator 1.00 ppb B
Peru 10.50 ppb B
LaSalle Not detected C
Mendota 8.07 ppb C
Lake Holiday 2.00 ppb A
Marseilles 19.10 ppb F
Oglesby Not detected C
Seneca Not detected B
Sheridan Not detected B
Earlville 2.90 ppb B
North Utica 5.31 ppb C
Leland Not detected B
Tonica Not detected B
Grand Ridge Not detected B
Naplate 2.06 ppb C
Lostant 0.65 ppb D
Ransom 1.00 ppb B
Cedar Point 4.85 ppb B
Kangley 1.00 ppb B
Rutland Not detected B
Dana 1.00 ppb B
Leonore 6.00 ppb B
Troy Grove Not detected B
Triumph Not detected B
Wedron 0.53 ppb C
Showing 26 cities
No active violations Active violations

About LaSalle County Drinking Water

LaSalle County is served by 21 water systems covering 26 communities. 92% have no open violations.

Of the communities reporting lead results, 16 recorded a detection, with a median of 2.06 ppb — 14% of the federal action level. 10 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 16 of them.

Frequently Asked Questions

Is LaSalle County tap water safe to drink?▼
92% of communities have no open violation. No community has PFAS above the federal limit on record.
What is the lead level in LaSalle County?▼
Among communities with a detection the median is 2.06 ppb, 14% of the 15 ppb action level. 10 reported none detected and 0 reported no result.
How many water systems serve LaSalle County?▼
21 community water systems serve 26 communities here.
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