Is Mountlake Terrace, WA tap water safe?
Data: U.S. EPA · How we read the data · How we check it
Summary
No federal limits exceeded in EPA data for City of Mountlake Terrace.
City of Mountlake Terrace supplies Mountlake Terrace (26,402 people).
Water system
City of Mountlake Terrace
26,402 people · Purchased surface water · EPA ID WA5357250
Buys treated water from Alderwood Water District.
| PFAS | Highest average | Limit |
|---|---|---|
| PFOA Not detected | – | 4 ppt |
| PFOS Not detected | – | 4 ppt |
| PFHxS Not detected | – | 10 ppt |
| PFNA Not detected | – | 10 ppt |
| HFPO-DA (GenX) Not detected | – | 10 ppt |
ppt = parts per trillion. "Highest average" is the highest average at any of the system's entry points, the way EPA compares results with the limits.
Lead: no results reported
Health-based violations since 2016: 0
Across Washington, 20 of 245 water systems EPA tested had PFAS above a 2024 federal limit, and 17 systems were above the lead action level in results from the last five years. Washington results.
Mountlake Terrace homes and lead pipes
Lead service lines and lead solder were allowed until 1986, so homes from before then are the ones to check. Renting? Ask your landlord what the service line is made of, because it's their pipe to replace. How to check your own line.
Housing: Census American Community Survey 2020–2024 5-year estimates for Mountlake Terrace city (tables B25034, B25003). Estimates for small places have a margin of error.
How nearby cities compare
| City | PFAS | Lead (90th pct.) |
|---|---|---|
| Lynnwood 2 mi City of Lynnwood | None above limits | – |
| Edmonds 3 mi City of Edmonds | None above limits | – |
| Shoreline 3 mi Northshore Utility District | None above limits | – |
| Bothell 5 mi Northshore Utility District | None above limits | – |
| Kirkland 8 mi Northshore Utility District | None above limits | – |
| Redmond 12 mi City of Redmond Water System | None above limits | 2 ppb |
Mountlake Terrace ZIP codes (1)
- 98043
Questions
Is Mountlake Terrace tap water safe to drink?
City of Mountlake Terrace has had no health-based violations since 2016. Utility data can't show lead from your own pipes: if your home was built before 1986, test your tap. Your utility's annual Consumer Confidence Report is the official summary.
Who supplies water in Mountlake Terrace, WA?
City of Mountlake Terrace, which serves 26,402 people.
Does Mountlake Terrace tap water have PFAS?
None detected above EPA's reporting limits. City of Mountlake Terrace had no PFAS detected in EPA's 2023–2025 testing. "Not detected" means below the reporting limit (about 2 to 20 ppt), not proven zero.
Do Mountlake Terrace homes have lead pipes?
Census estimates put 61% of Mountlake Terrace homes as built before 1980 (Washington: 43%). Lead service lines and lead solder were allowed until 1986, so older homes are more likely to have them. City of Mountlake Terrace's service line inventory says what your line is made of. The only way to know for your home is to check the line where it enters the house and test your tap.
Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.