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Tap water quality report

Mountlake Terrace City of

EPA monitoring tested this supplier for 41 contaminants and detected 7. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

41
contaminants tested
7
detected
26,402
people served
0
health-based violations
Washington rankingsLead in WashingtonPFAS in Washington
Water source
SWP
Ownership
Local government
Counties served
Snohomish

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

0
health-based violations
12
violations on file
0
still open
ViolationTypeStatusPeriod
Other Monitoring Resolved 2024-07-01
MR Monitoring Resolved 2020-01-01 → 2020-03-31
MR Monitoring Resolved 2020-01-01 → 2020-03-31
MR Monitoring Resolved 2019-01-01 → 2019-03-31
Other Monitoring Resolved 2017-07-01
Other Monitoring Resolved 2016-07-01
Other Monitoring Resolved 2015-07-01
Other Monitoring Resolved 2014-07-01
Other Monitoring Resolved 2013-07-01
Other Monitoring Resolved 2012-07-01

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Total Haloacetic Acids (HAA5)
47.28 µg/L 79%
of the EPA limit 60 µg/L
worst single sample: 52.5 µg/L
125/125 SYR4 2012–2019
Dichloroacetic Acid
18.69 µg/L
No EPA limit set
worst single sample: 21.2 µg/L
123/123 SYR4 2012–2019
Chloroform
58.425 µg/L
No EPA limit set
worst single sample: 67.1 µg/L
122/122 SYR4 2012–2019
TTHM
61.115 µg/L 76%
of the EPA limit 80 µg/L
worst single sample: 70.1 µg/L
122/122 SYR4 2012–2019
Trichloroacetic Acid
28.7 µg/L
No EPA limit set
worst single sample: 32.5 µg/L
121/121 SYR4 2012–2019
Bromodichloromethane
2.7 µg/L
No EPA limit set
worst single sample: 3 µg/L
94/94 SYR4 2012–2019
Monochloroacetic Acid
3.8 µg/L
No EPA limit set
worst single sample: 4.5 µg/L
21/125 SYR4 2012–2019
34 contaminants tested, none detected
11Cl-PF3OUdS4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaBromoformDibromoacetic AcidDibromochloromethaneHfpo-DaMonobromoacetic AcidNetfosaaNfdhaNmefosaaPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaLithium

Utility contact

Contact
Shawn Hjert

Frequently asked questions about Mountlake Terrace City of

Is Mountlake Terrace City of tap water safe to drink?

EPA monitoring detected 7 contaminants in Mountlake Terrace City of's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Mountlake Terrace City of's water?

EPA monitoring detected Total Haloacetic Acids (HAA5), Dichloroacetic Acid, Chloroform, TTHM, Trichloroacetic Acid, and others. The full list with the level and data source for each is above.

How many people does Mountlake Terrace City of serve?

Mountlake Terrace City of reports serving 26,402 people in Washington, per its EPA record.

Has Mountlake Terrace City of had any water quality violations?

The EPA has 12 violations on file for Mountlake Terrace City of, of which 0 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.