F0/100
ISSAQUAH WATER SYSTEM — Water Quality Report 2026
Serving 43,584 people · Washington
Water Source
Purchased Surface Water
County
—
System ID
WA5336350
Violations
172
Contaminant Test Results
2 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Copper (90th percentile) | 1.59 mg/L | 1.30 mg/L | Over Limit |
Lead (90th percentile) | 0.001 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2015.
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 ISSAQUAH WATER SYSTEM
Is ISSAQUAH WATER SYSTEM water safe to drink?
ISSAQUAH WATER SYSTEM water receives a grade of F (0/100), which is considered failing. 1 contaminant(s) exceed EPA legal limits and 172 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has ISSAQUAH WATER SYSTEM detected?
70 contaminants were tested in ISSAQUAH WATER SYSTEM's water. Notable contaminants include Copper (90th percentile), Lead (90th percentile). 1 exceed EPA legal limits (MCLs). 2 exceed EPA health goals (MCLGs).
Does ISSAQUAH WATER SYSTEM have any EPA violations?
Yes, ISSAQUAH WATER SYSTEM has 172 EPA violation(s) on record, with the most recent in 2015. Violation types include Other, MR, MCL. 4 are health-based violations.
How many people does ISSAQUAH WATER SYSTEM serve?
ISSAQUAH WATER SYSTEM serves approximately 43,584 people, Washington.
What type of water does ISSAQUAH WATER SYSTEM provide?
ISSAQUAH WATER SYSTEM 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 WA5336350.
How does ISSAQUAH WATER SYSTEM compare to other utilities in Washington?
ISSAQUAH WATER SYSTEM 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.