Water Quality

The City of Issaquah is committed to delivering the best quality drinking water. To that end, we remain vigilant in meeting the challenges of source water protection, water conservation and community education while continuing to serve the needs of all of our water users.

Water Quality Reports

Each year, we take hundreds of water samples to determine the presence of any radioactive, biological, inorganic, volatile organic or synthetic organic contaminants. Our annual Water Quality Reports illustrate the results of those tests, as well as other valuable information.

Most Recent Water Quality Report

All Available Water Quality Reports



After publication of its 2014 Water Quality Report, the City of Issaquah received the following corrected information from the testing lab concerning Well 4 (note that water from Well 4 was blended with at least one other well before it was distributed). Learn more about how the City of Issaquah is now filtering PFAS from its drinking water.

 (units of measurement)
 Well 4 (2014)
PFBS (ppb)ND
PFHpA (ppb)
PFHxS (ppb)
PFNA (ppb)
PFOA (ppb)0.0200
PFOS (ppb)0.514
ND — not detected


While 2009 test results for combined radium (pCi/L) — which found no violation — were included in the City's 2009 Water Quality Report, the same results were inadvertently not included in the 2010 Water Quality Report. Subsequent samplings in May and October of 2012 found no level of combined radium.