B60/100
LAKE OSWEGO MUNICIPAL WATER — Water Quality Report 2026
Serving 40,000 people · Oregon
Water Source
Purchased Surface Water
County
—
System ID
OR4100457
Violations
36
Contaminant Test Results
EPA Violation History
2
Violations (last 5yr)
0
Unresolved
0
Health-Related
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2025 – September 2, 2025Enforcement: Resolving — corrective action underway
TIER 3Resolved
Surface water treatment technique failure
When: July 1, 2024 – July 3, 2024Enforcement: 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 LAKE OSWEGO MUNICIPAL WATER
Is LAKE OSWEGO MUNICIPAL WATER water safe to drink?
LAKE OSWEGO MUNICIPAL WATER water receives a grade of B (60/100), which is considered good. Out of 69 contaminants tested, none exceed EPA legal limits. The water meets federal safety standards.
What contaminants has LAKE OSWEGO MUNICIPAL WATER detected?
69 contaminants were tested in LAKE OSWEGO MUNICIPAL WATER's water. No contaminants exceed EPA legal limits or health goals, indicating good water quality management.
Does LAKE OSWEGO MUNICIPAL WATER have any EPA violations?
Yes, LAKE OSWEGO MUNICIPAL WATER has 36 EPA violation(s) on record, with the most recent in 2025. Violation types include Other, MR, TT. 1 are health-based violations.
How many people does LAKE OSWEGO MUNICIPAL WATER serve?
LAKE OSWEGO MUNICIPAL WATER serves approximately 40,000 people, Oregon.
What type of water does LAKE OSWEGO MUNICIPAL WATER provide?
LAKE OSWEGO MUNICIPAL WATER sources its water from purchased surface water. Surface water comes from rivers, lakes, or reservoirs and typically requires more extensive treatment. The utility's system ID is OR4100457.
How does LAKE OSWEGO MUNICIPAL WATER compare to other utilities in Oregon?
LAKE OSWEGO MUNICIPAL WATER scores 60/100 with a grade of B (good). This is an above-average performance for utilities statewide. Visit our Oregon state page for a full comparison of water systems.