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Mountlake Terrace, WA Tap Water Quality 2026

Water quality report for Mountlake Terrace, WA — PFAS, lead and copper results, violation history and state inspection findings from EPA SDWIS.

A look at Mountlake Terrace's drinking water using EPA enforcement records: violations, lead and copper results, PFAS sampling and state inspection findings.

Main Utility: Mountlake Terrace City Of PWSID: WA5357250 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead has not been reported for this system and no violations are open. No PFAS was detected.

B

Mountlake Terrace earns a B for water quality

Graded on violations and PFAS, with state inspection findings. Lead not reported.

Lead: not reported
PFAS tested, none detected
7 violations since 2015, 0 health-based
No violations currently open
Mountlake Terrace's lead level vs. all Washington community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: — 0% of the federal action level
✓ Lower lead than % of Washington utilities
Population Served
21259
~9290 connections
Water Source
Surface water
Purchased from another system — SDWIS source code SWP
Active Violations
0
7 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
0% of EPA action level
Action level: 15 ppb
No lead result has been reported for this system in the current window. That is a gap in state reporting, not a finding of safety.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
Consumer Confidence Rule OTHER — — 2024 Resolved
TTHM MONITORING AND REPORTING — 0.080 mg/L 2020 Resolved
Total Haloacetic Acids (HAA5) MONITORING AND REPORTING — 0.060 mg/L 2020 Resolved
TTHM MONITORING AND REPORTING — 0.080 mg/L 2019 Resolved
Consumer Confidence Rule OTHER — — 2017 Resolved
Consumer Confidence Rule OTHER — — 2016 Resolved
Consumer Confidence Rule OTHER — — 2015 Resolved
Understanding violation types MCL violations mean a contaminant exceeded the federal maximum limit — the most serious type.
TT (Treatment Technique) violations mean required treatment procedures weren't followed, but don't necessarily mean contamination occurred.

Violation History

7 violations are on record since 2015, of which 0 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Mountlake Terrace City Of
PWSID WA5357250
Water source Surface water — Purchased from another system — SDWIS source code SWP
Population served 21,259
Service connections 9,290
Systems serving this area 6
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Mountlake Terrace tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open.
Does Mountlake Terrace water have PFAS? ▼
It was tested for the six regulated PFAS compounds and none were detected.
Who supplies water to Mountlake Terrace? ▼
Mountlake Terrace City Of (PWSID WA5357250), one of 6 systems serving this area. Surface water. Purchased from another system — SDWIS source code SWP
When was this system last inspected? ▼
It was last inspected on 2025-06-25. No significant deficiencies were recorded.

What Should Mountlake Terrace Residents Do?

1
Read your annual water report
Your supplier publishes a Consumer Confidence Report each July covering the prior year.
2
Check for a lead service line
Lead reaches tap water mainly through service lines and household plumbing. Suppliers now publish an inventory identifying lead lines.
3
Flush before drinking
If water has sat in pipes more than six hours, run the cold tap for two minutes before drinking or cooking.

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