F0/100
MASON CITY WATER DEPARTMENT — Water Quality Report 2026
Serving 27,338 people · Iowa
Water Source
Groundwater
County
—
System ID
IA1750048
Violations
142
Contaminant Test Results
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
chlorate | 244.00 µg/L | — | Above Goal |
Lead (90th percentile) | 0.003 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
1
Violation (last 5yr)
0
Unresolved
0
Health-Related
TIER 3Resolved
Monitoring Violation
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: June 1, 2024 – June 30, 2024Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Frequently Asked Questions About MASON CITY WATER DEPARTMENT
Is MASON CITY WATER DEPARTMENT water safe to drink?
MASON CITY WATER DEPARTMENT water receives a grade of F (0/100), which is considered failing. 0 contaminant(s) exceed EPA legal limits and 142 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has MASON CITY WATER DEPARTMENT detected?
66 contaminants were tested in MASON CITY WATER DEPARTMENT's water. Notable contaminants include Lead (90th percentile), chlorate. No contaminants exceed EPA legal limits. 2 exceed EPA health goals (MCLGs).
Does MASON CITY WATER DEPARTMENT have any EPA violations?
Yes, MASON CITY WATER DEPARTMENT has 142 EPA violation(s) on record, with the most recent in 2024. Violation types include MON, MCL, MR. 18 are health-based violations.
How many people does MASON CITY WATER DEPARTMENT serve?
MASON CITY WATER DEPARTMENT serves approximately 27,338 people, Iowa. The system provides water to 1 community: Mason City.
What type of water does MASON CITY WATER DEPARTMENT provide?
MASON CITY WATER DEPARTMENT sources its water from groundwater. Groundwater is pumped from underground aquifers, which often provides natural filtration. The utility's system ID is IA1750048.
How does MASON CITY WATER DEPARTMENT compare to other utilities in Iowa?
MASON CITY WATER DEPARTMENT scores 0/100 with a grade of F (failing). This score suggests significant water quality concerns relative to other utilities. Visit our Iowa state page for a full comparison of water systems.