F0/100
Mattawa City of — Water Quality Report 2026
Serving 5,015 people · Washington
Water Source
Groundwater
County
—
System ID
WA5352000
Violations
177
Contaminant Test Results
EPA Violation History
2
Violations (last 5yr)
0
Unresolved
1
Health-Related
TIER 1 — URGENTResolved
Maximum Contaminant Level Violation
When: June 1, 2024 – June 30, 2024Rule: Total Coliform RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2023 – September 20, 2023Enforcement: 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 Mattawa City of
Is Mattawa City of water safe to drink?
Mattawa City of water receives a grade of F (0/100), which is considered failing. 0 contaminant(s) exceed EPA legal limits and 177 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has Mattawa City of detected?
31 contaminants were tested in Mattawa City of's water. No contaminants exceed EPA legal limits or health goals, indicating good water quality management.
Does Mattawa City of have any EPA violations?
Yes, Mattawa City of has 177 EPA violation(s) on record, with the most recent in 2024. Violation types include MCL, Other, MR. 6 are health-based violations.
How many people does Mattawa City of serve?
Mattawa City of serves approximately 5,015 people, Washington.
What type of water does Mattawa City of provide?
Mattawa City of sources its water from groundwater. Groundwater is pumped from underground aquifers, which often provides natural filtration. The utility's system ID is WA5352000.
How does Mattawa City of compare to other utilities in Washington?
Mattawa City of scores 0/100 with a grade of F (failing). This score suggests significant water quality concerns relative to other utilities. Visit our Washington state page for a full comparison of water systems.