Is Issaquah, Washington tap water safe?
12 water systems report serving Issaquah. Your water depends on which one serves your address. Check your bill if unsure. This list is matched from the ZIP codes in this place, so it may include nearby systems.
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Sammamish Plateau Water & Sewer
Serves 79,362 people · Surface water · Full report →
No health-based violations in the last 5 years; PFOA/PFOS average above the 4 ppt federal limit: PFOS; Other PFAS above 2024 limits (rule proposed for repeal): PFHxS, Hazard Index; Lead 90th percentile below the action level (2025).
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Issaquah Water System
Serves 43,584 people · Surface water · Full report →
No health-based violations in the last 5 years; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2022).
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King County Water District No 90
Serves 20,100 people · Surface water · Full report →
No health-based violations in the last 5 years; 1 monitoring/reporting violation; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
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Mirrormont
Serves 2,083 people · Groundwater · Full report →
No health-based violations in the last 5 years; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2024).
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Preston Industrial Park Water Assn
Serves 930 people · Groundwater · Full report →
No health-based violations in the last 5 years; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2025).
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Four Lakes
Serves 212 people · Groundwater · Full report →
No health-based violations in the last 5 years; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2024).
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Four Creeks Ranch Water System
Serves 150 people · Groundwater · Full report →
No health-based violations in the last 5 years; 2 monitoring/reporting violations; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2024).
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Twenty-Three 800 Tiger Mountain
Serves 129 people · Groundwater · Full report →
No health-based violations in the last 5 years; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2024).
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The Meadows Water System LLC
Serves 127 people · Groundwater · Full report →
No health-based violations in the last 5 years; 1 monitoring/reporting violation; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2024).
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Issaquah Valley Water Assn #1
Serves 80 people · Groundwater · Full report →
No health-based violations in the last 5 years; 1 monitoring/reporting violation; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2025).
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Mazama Woods
Serves 45 people · Groundwater · Full report →
No health-based violations in the last 5 years; 1 monitoring/reporting violation; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2023).
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Tiger Mtn Tracts
Serves 30 people · Groundwater · Full report →
No health-based violations in the last 5 years; 6 monitoring/reporting violations; No UCMR 5 PFAS results on file; Lead 90th percentile below the action level (2023).