Water Quality Report · Updated May 12, 2026
HIGHLINE WATER DISTRICT
HIGHLINE WATER DISTRICT delivers tap water graded F (50/100) by TapWaterSafety.org. The utility serves approximately 100,170 residents in Kent, Washington using surface water (purchased). The most significant water quality concerns are: PFAS contamination; Perfluorohexane sulfonate (PFHXS) significantly above health guideline; Total PFOS and PFOA significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline.
Is Kent tap water safe to drink?
HIGHLINE WATER DISTRICT delivers tap water that earns a grade of F (50/100) from TapWaterSafety.org — a poor rating, with significant contamination concerns and/or recent violations.
The utility serves 100,170 residents in Kent, drawing from surface water (purchased).
Public testing data identifies 15 contaminants in this water above EWG's health-based guidelines, including: Perfluorohexane sulfonate (PFHXS), Total PFOS and PFOA, Haloacetic acids (HAA9), Perfluorononanoic acid (PFNA), Haloacetic acids (HAA5), Total trihalomethanes (TTHMs), Trichloroacetic acid, Bromodichloromethane, Chloroform, Dichloroacetic acid, Bromochloroacetic acid, Dibromochloromethane, Perfluorooctanoic acid (PFOA), Perfluorooctane sulfonate (PFOS), Chromium (hexavalent). 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 Kent residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for HIGHLINE WATER DISTRICT.
PFAS contamination
Severe concernPerfluorononanoic acid (PFNA), Perfluorooctane sulfonate (PFOS) detected. PFAS are persistent chemicals linked to cancer and immune effects with no known safe exposure threshold.
Perfluorohexane sulfonate (PFHXS) significantly above health guideline
Moderate concernPerfluorohexane sulfonate (PFHXS) detected at 1.51 ppt, 1506x above the EWG health guideline of 0.001 ppt.
Total PFOS and PFOA significantly above health guideline
Moderate concernTotal PFOS and PFOA detected at 7.13 ppt, 1019x above the EWG health guideline of 0.007 ppt.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 31.4 ppb, 524x above the EWG health guideline of 0.06 ppb.
Contact HIGHLINE WATER DISTRICT
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 Kent
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 50/100 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 |
|---|---|---|---|---|---|---|---|---|
| Perfluorohexane sulfonate (PFHXS) PFAS |
1.51 ppt | 0.001 | 10.0 | — | — | — | — | 1506× over |
| Total PFOS and PFOA PFAS |
7.13 ppt | 0.007 | — | 100 | 100 | 0.007 | — | 1019× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
31.4 ppb | 0.06 | — | — | — | — | — | 524× over |
| Perfluorononanoic acid (PFNA) PFAS |
3.13 ppt | 0.006 | 10.0 | — | — | — | — | 521× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
23.5 ppb | 0.1 | 60.0 | 60 | — | — | — | 235× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
26.0 ppb | 0.15 | 80.0 | 100 | — | — | — | 173× over |
| Trichloroacetic acid Disinfection byproduct |
12.0 ppb | 0.1 | — | — | — | — | — | 120× over |
| Bromodichloromethane Disinfection byproduct |
3.25 ppb | 0.06 | — | — | — | — | — | 54× over |
| Chloroform Disinfection byproduct |
21.6 ppb | 0.4 | — | — | — | — | — | 54× over |
| Dichloroacetic acid Disinfection byproduct |
10.8 ppb | 0.2 | — | — | — | — | — | 54× over |
| Bromochloroacetic acid Disinfection byproduct |
0.928 ppb | 0.02 | — | — | — | — | — | 46× over |
| Dibromochloromethane Disinfection byproduct |
1.09 ppb | 0.1 | — | — | — | — | — | 11× over |
| Perfluorooctanoic acid (PFOA) PFAS |
0.514 ppt | 0.09 | 4.0 | 100 | 100 | 0.007 | — | 5.7× over |
| Perfluorooctane sulfonate (PFOS) PFAS |
1.27 ppt | 0.3 | 4.0 | 100 | 100 | 1 | — | 4.2× over |
| Chromium (hexavalent) Heavy metal |
0.0786 ppb | 0.02 | — | — | — | — | — | 3.9× over |
| Dibromoacetic acid Disinfection byproduct |
0.0235 ppb | 0.03 | — | — | — | — | — | Below guideline |
| Chlorate Disinfection byproduct |
39.8 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
0.992 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Bromoform Disinfection byproduct |
0.00897 ppb | 0.5 | — | — | — | — | — | Below guideline |
| Monochloroacetic acid Disinfection byproduct |
0.668 ppb | 53.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.933 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Perfluorobutanoic Acid (PFBA) PFAS |
0.248 ppt | 1000.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.0636 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.313 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| PFOS + PFOA + PFHxS + PFNA PFAS |
17.1 ppt | — | — | 100 | 100 | 0.007 | — | 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.
HIGHLINE WATER DISTRICT 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 Kent water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.