Water Quality Report · Updated May 12, 2026
REDMOND WATER SYSTEM CITY OF
REDMOND WATER SYSTEM CITY OF delivers tap water graded D (61/100) by TapWaterSafety.org. The utility serves approximately 163,335 residents in Redmond, Washington using surface water (purchased). The most significant water quality concerns are: PFAS contamination; Haloacetic acids (HAA9) significantly above health guideline; Haloacetic acids (HAA5) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline.
Is Redmond tap water safe to drink?
REDMOND WATER SYSTEM CITY OF delivers tap water that earns a grade of D (61/100) from TapWaterSafety.org — a below-average rating, with multiple concerns including pfas contamination.
The utility serves 163,335 residents in Redmond, drawing from surface water (purchased).
Public testing data identifies 14 contaminants in this water above EWG's health-based guidelines, including: Haloacetic acids (HAA9), Haloacetic acids (HAA5), Total trihalomethanes (TTHMs), Trichloroacetic acid, Chloroform, Dichloroacetic acid, Bromodichloromethane, Bromochloroacetic acid, Dibromoacetic acid, Dibromochloromethane, Nitrate, Nitrate and nitrite, Chromium (hexavalent), Perfluorooctane sulfonate (PFOS). For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
Quick actions for Redmond residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for REDMOND WATER SYSTEM CITY OF.
PFAS contamination
Severe concernPerfluorooctane sulfonate (PFOS) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 22.8 ppb, 380x above the EWG health guideline of 0.06 ppb.
Haloacetic acids (HAA5) significantly above health guideline
Moderate concernHaloacetic acids (HAA5) detected at 23.2 ppb, 232x above the EWG health guideline of 0.1 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 25.3 ppb, 169x above the EWG health guideline of 0.15 ppb.
Contact REDMOND WATER SYSTEM CITY OF
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for Redmond
Filters matched to the specific contaminants in this water supply.
Reverse Osmosis or NSF P473 certified carbon
$80-$750Activated carbon and RO are the only technologies proven to remove PFAS at certified levels.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
Score breakdown
This utility's overall score of 61/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Haloacetic acids (HAA9) Disinfection byproduct |
22.8 ppb | 0.06 | — | — | — | — | — | 380× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
23.2 ppb | 0.1 | 60.0 | 60 | — | — | — | 232× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
25.3 ppb | 0.15 | 80.0 | 100 | — | — | — | 169× over |
| Trichloroacetic acid Disinfection byproduct |
12.5 ppb | 0.1 | — | — | — | — | — | 125× over |
| Chloroform Disinfection byproduct |
22.3 ppb | 0.4 | — | — | — | — | — | 56× over |
| Dichloroacetic acid Disinfection byproduct |
9.78 ppb | 0.2 | — | — | — | — | — | 49× over |
| Bromodichloromethane Disinfection byproduct |
2.09 ppb | 0.06 | — | — | — | — | — | 35× over |
| Bromochloroacetic acid Disinfection byproduct |
0.32 ppb | 0.02 | — | — | — | — | — | 16× over |
| Dibromoacetic acid Disinfection byproduct |
0.176 ppb | 0.03 | — | — | — | — | — | 5.9× over |
| Dibromochloromethane Disinfection byproduct |
0.524 ppb | 0.1 | — | — | — | — | — | 5.2× over |
| Nitrate Inorganic |
0.707 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 5.1× over |
| Nitrate and nitrite Inorganic |
0.707 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 5.1× over |
| Chromium (hexavalent) Heavy metal |
0.0988 ppb | 0.02 | — | — | — | — | — | 4.9× over |
| Perfluorooctane sulfonate (PFOS) PFAS |
0.5 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 1.7× over |
| Chlorate Disinfection byproduct |
43.6 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Bromoform Disinfection byproduct |
0.0907 ppb | 0.5 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
4.57 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Vanadium Other |
0.616 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.725 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Perfluorobutane sulfonate (PFBS) PFAS |
0.84 ppt | 2000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.0652 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Lithium Other |
1.3 ppb | — | — | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
REDMOND WATER SYSTEM CITY OF service area
This water system serves 1 community in King County, Washington. Click any city for its dedicated tap water quality page.
Find the right filter for Redmond water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.