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Public water system record

Mason City

Serves Mason City, Mason County, IL · 2,558 people served

Federal records show no health-based violations and 1 monitoring/reporting issue for Mason City in the last ten years. At least one of these issues remains unresolved.

  • IL1250350
  • MASON CITY
  • IL
  • 2,558 served

System profile

Source water Groundwater
ZIP 62664
EPA system ID IL1250350

Verify this system on EPA ECHO →

Health-based violations, last 10 years
0
Resolved
0
Unresolved
0
Any acute record
No
Monitoring issues, last 10 years
1

Key facts

  • Mason City draws water from 3 wells.
  • Most recent formal enforcement: signed compliance agreement by Illinois, June 2006.
  • Record on file since 1977, with 15 health-based violations before October 19, 2016.
  • Lead pipe inventory: 0 lead and 0 unknown out of 1,001 service lines.

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Health-based violations

Since October 2016

Violation data reflects EPA records through March 2026. For the most current status, visit the EPA ECHO database.

None since October 2016.

Monitoring and reporting issues

Since October 2016

Missed tests or reports, not contaminants found above a limit.

Issue Start date Status
LEAD AND COPPER RULE REVISIONS
RPT
 Jul 2, 2025 Active

Full record since 1977

EPA's records for Mason City go back to 1977. Before October 19, 2016 they list 15 health-based violations (15 resolved) and 1 monitoring or reporting violation.

Violations that began in Health-based Monitoring and reporting
1970s 0 1
2000s 15 0
2020s 0 1

Most recent health-based violation before October 19, 2016: Arsenic, began July 2009, Resolved.

Show all 15 health-based violations before October 19, 2016
Contaminant Start date Status
Arsenic
Contaminant limit exceeded
Measured 0.014 mg/L, federal limit 0.01 mg/L (1.4 times the limit)
 Jul 1, 2009 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.052 mg/L, federal limit 0.01 mg/L (5.2 times the limit)
 Apr 1, 2009 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.037 mg/L, federal limit 0.01 mg/L (3.7 times the limit)
 Jan 1, 2009 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.017 mg/L, federal limit 0.01 mg/L (1.7 times the limit)
 Oct 1, 2008 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.016 mg/L, federal limit 0.01 mg/L (1.6 times the limit)
 Jul 1, 2008 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.025 mg/L, federal limit 0.01 mg/L (2.5 times the limit)
 Apr 1, 2008 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.025 mg/L, federal limit 0.01 mg/L (2.5 times the limit)
 Jan 1, 2008 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.024 mg/L, federal limit 0.01 mg/L (2.4 times the limit)
 Oct 1, 2007 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.022 mg/L, federal limit 0.01 mg/L (2.2 times the limit)
 Jul 1, 2007 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.022 mg/L, federal limit 0.01 mg/L (2.2 times the limit)
 Apr 1, 2007 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.022 mg/L, federal limit 0.01 mg/L (2.2 times the limit)
 Jan 1, 2007 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.022 mg/L, federal limit 0.01 mg/L (2.2 times the limit)
 Oct 1, 2006 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.024 mg/L, federal limit 0.01 mg/L (2.4 times the limit)
 Jul 1, 2006 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.018 mg/L, federal limit 0.01 mg/L (1.8 times the limit)
 Apr 1, 2006 Resolved
Arsenic
Contaminant limit exceeded
Measured 0.023 mg/L, federal limit 0.01 mg/L (2.3 times the limit)
 Jan 23, 2006 Resolved

Enforcement actions

Illinois regulators took 1 formal enforcement action against Mason City in 2006. The most recent was a signed compliance agreement in June 2006.

Date By Action Violations covered
Jun 20, 2006 Illinois Signed compliance agreement 15 violations (15 health-based): Arsenic

Where the water comes from

Mason City draws water from 3 wells. 1 smaller public system such as schools, businesses or campgrounds buys water from Mason City.

Annual water quality report

Mason City must give its customers an annual water quality report (Consumer Confidence Report) by July 1, with the levels its tests found in the previous year.

Where the state allows it, systems serving fewer than 10,000 people may publish the report in a local newspaper or news site instead of mailing it, and must provide a copy on request.

Find a posted report with EPA's Consumer Confidence Report search

Testing your own water

To test the water at your tap, or a private well this record does not cover, use a laboratory certified for drinking water by Illinois.

Certified drinking water labs by state EPA guidance for private wells