King County, Washington
122 ZIP codes · Avg score 91/100 · Grade A · Updated 2026-06-03
Compared to state averages, King County scores well — its 122 ZIP codes sit above the baseline for tap water quality.
How King County Compares
How King County Compares
King County scores 13 points above the Washington state average (78/100) and 23 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: King County, Washington
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 8.8 (asthma 9.7%, diabetes 7.3%)
Estimated additional annual cost per homeowner: $2,076, driven primarily by sea_level
Infrastructure: 0.328% avg pipe failure probability, 5% of ZIPs at high risk
54.5% of homes built before 1978 (lead paint era)
Violation History (2024–2025)
→ Stable trendEPA violation counts by year across King County water systems. Health-based shown in red, total in blue.
Peak year: 2025 with 2 violations. Past 5 years: 3 total (3 health-based).
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $2,076
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
964,697 housing units in King County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in King County
Remediation costs are relatively manageable for most homeowners in King County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for King County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in King County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | King County Water District #125 | 17,546 | 63 |
| 2 | Skyway Water & Sewer | 12,036 | 63 |
| 3 | Seattle Public Utilities | 1,091,904 | 61 |
| 4 | King County Water District #20 | 38,974 | 61 |
| 5 | Ravenwing Ranch | 250 | 61 |
94 total water systems serve King County.
All ZIP Codes in King County
122 ZIP codes tracked in King County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 98035 | Kent | 99 | A | 1 | — |
| 2 | 98064 | Kent | 99 | A | 1 | — |
| 3 | 98089 | Kent | 99 | A | 1 | — |
| 4 | 98111 | Seattle | 99 | A | 1 | — |
| 5 | 98113 | Seattle | 99 | A | 1 | — |
| 6 | 98114 | Seattle | 99 | A | 1 | — |
| 7 | 98124 | Seattle | 99 | A | 1 | — |
| 8 | 98127 | Seattle | 99 | A | 1 | — |
| 9 | 98129 | Seattle | 99 | A | 1 | — |
| 10 | 98131 | Seattle | 99 | A | 1 | — |
| 11 | 98132 | Seattle | 99 | A | 1 | — |
| 12 | 98134 | Seattle | 99 | A | 1 | $385K |
| 13 | 98138 | Seattle | 99 | A | 1 | — |
| 14 | 98139 | Seattle | 99 | A | 1 | — |
| 15 | 98141 | Seattle | 99 | A | 1 | — |
| 16 | 98145 | Seattle | 99 | A | 1 | — |
| 17 | 98154 | Seattle | 99 | A | 1 | — |
| 18 | 98158 | Seattle | 99 | A | 1 | — |
| 19 | 98160 | Seattle | 99 | A | 1 | — |
| 20 | 98161 | Seattle | 99 | A | 1 | — |
| 21 | 98164 | Seattle | 99 | A | 1 | $715K |
| 22 | 98165 | Seattle | 99 | A | 1 | — |
| 23 | 98170 | Seattle | 99 | A | 1 | — |
| 24 | 98171 | Seattle | 99 | A | 1 | — |
| 25 | 98174 | Seattle | 99 | A | 1 | — |
| 26 | 98175 | Seattle | 99 | A | 1 | — |
| 27 | 98181 | Seattle | 99 | A | 1 | — |
| 28 | 98185 | Seattle | 99 | A | 1 | — |
| 29 | 98189 | Seattle | 99 | A | 1 | — |
| 30 | 98190 | Seattle | 99 | A | 1 | — |
| 31 | 98191 | Seattle | 99 | A | 1 | — |
| 32 | 98194 | Seattle | 99 | A | 1 | — |
| 33 | 98195 | Seattle | 99 | A | 1 | — |
| 34 | 98051 | Ravensdale | 98 | A | 2 | $703K |
| 35 | 98073 | Redmond | 97 | A | 2 | — |
| 36 | 98010 | Black Diamond | 95 | A | 0 | $793K |
| 37 | 98030 | Kent | 95 | A | 1 | $540K |
| 38 | 98042 | Kent | 95 | A | 1 | $613K |
| 39 | 98063 | Federal Way | 95 | A | 3 | — |
| 40 | 98093 | Federal Way | 95 | A | 3 | — |
| 41 | 98102 | Seattle | 95 | A | 1 | $989K |
| 42 | 98103 | Seattle | 95 | A | 1 | $1013K |
| 43 | 98104 | Seattle | 95 | A | 1 | $663K |
| 44 | 98105 | Seattle | 95 | A | 1 | $1261K |
| 45 | 98107 | Seattle | 95 | A | 1 | $925K |
| 46 | 98109 | Seattle | 95 | A | 1 | $986K |
| 47 | 98118 | Seattle | 95 | A | 1 | $746K |
| 48 | 98119 | Seattle | 95 | A | 1 | $1033K |
| 49 | 98121 | Seattle | 95 | A | 1 | $797K |
| 50 | 98122 | Seattle | 95 | A | 1 | $929K |
| 51 | 98144 | Seattle | 95 | A | 1 | $890K |
| 52 | 98148 | Seattle | 95 | A | 1 | $576K |
| 53 | 98168 | Seattle | 95 | A | 1 | $501K |
| 54 | 98188 | Seattle | 95 | A | 1 | $453K |
| 55 | 98055 | Renton | 94 | A | 2 | $562K |
| 56 | 98056 | Renton | 94 | A | 2 | $726K |
| 57 | 98057 | Renton | 94 | A | 2 | $607K |
| 58 | 98059 | Renton | 94 | A | 2 | $810K |
| 59 | 98077 | Woodinville | 94 | A | 3 | $1132K |
| 60 | 98083 | Kirkland | 94 | A | 2 | — |
| 61 | 98053 | Redmond | 93 | A | 2 | $1156K |
| 62 | 98071 | Auburn | 93 | A | 4 | — |
| 63 | 98003 | Federal Way | 91 | A | 3 | $429K |
| 64 | 98022 | Enumclaw | 90 | A | 1 | $577K |
| 65 | 98031 | Kent | 90 | A | 1 | $552K |
| 66 | 98032 | Kent | 90 | A | 1 | $473K |
| 67 | 98106 | Seattle | 90 | A | 1 | $667K |
| 68 | 98108 | Seattle | 90 | A | 1 | $694K |
| 69 | 98112 | Seattle | 90 | A | 1 | $1407K |
| 70 | 98115 | Seattle | 90 | A | 1 | $1042K |
| 71 | 98116 | Seattle | 90 | A | 1 | $917K |
| 72 | 98117 | Seattle | 90 | A | 1 | $1028K |
| 73 | 98125 | Seattle | 90 | A | 1 | $845K |
| 74 | 98126 | Seattle | 90 | A | 1 | $752K |
| 75 | 98133 | Seattle | 90 | A | 1 | $719K |
| 76 | 98136 | Seattle | 90 | A | 1 | $900K |
| 77 | 98146 | Seattle | 90 | A | 1 | $642K |
| 78 | 98155 | Seattle | 90 | A | 1 | $758K |
| 79 | 98177 | Seattle | 90 | A | 1 | $996K |
| 80 | 98178 | Seattle | 90 | A | 1 | $628K |
| 81 | 98198 | Seattle | 90 | A | 1 | $527K |
| 82 | 98199 | Seattle | 90 | A | 1 | $1160K |
| 83 | 98029 | Issaquah | 89 | A | 4 | $964K |
| 84 | 98033 | Kirkland | 89 | A | 2 | $1260K |
| 85 | 98034 | Kirkland | 89 | A | 2 | $875K |
| 86 | 98070 | Vashon | 89 | A | 4 (1 health) | $718K |
| 87 | 98072 | Woodinville | 89 | A | 3 | $1067K |
| 88 | 98009 | Bellevue | 88 | A | 0 | — |
| 89 | 98015 | Bellevue | 88 | A | 0 | — |
| 90 | 98052 | Redmond | 88 | A | 2 | $1108K |
| 91 | 98074 | Sammamish | 88 | A | 4 | $1212K |
| 92 | 98075 | Sammamish | 88 | A | 4 | $1458K |
| 93 | 98005 | Bellevue | 87 | A | 0 | $1373K |
| 94 | 98040 | Mercer Island | 87 | A | 0 | $1884K |
| 95 | 98023 | Federal Way | 86 | A | 3 | $546K |
| 96 | 98024 | Fall City | 85 | A | 0 | $1005K |
| 97 | 98041 | Bothell | 85 | A | 4 | — |
| 98 | 98166 | Seattle | 85 | A | 1 | $786K |
| 99 | 98288 | Skykomish | 85 | A | 1 | $442K |
| 100 | 98001 | Auburn | 84 | B | 4 | $539K |
| 101 | 98002 | Auburn | 84 | B | 4 | $398K |
| 102 | 98011 | Bothell | 84 | B | 4 | $888K |
| 103 | 98058 | Renton | 84 | B | 2 | $627K |
| 104 | 98092 | Auburn | 84 | B | 4 | $595K |
| 105 | 98004 | Bellevue | 82 | B | 0 | $2000K |
| 106 | 98006 | Bellevue | 82 | B | 0 | $1234K |
| 107 | 98007 | Bellevue | 82 | B | 0 | $935K |
| 108 | 98008 | Bellevue | 82 | B | 0 | $1130K |
| 109 | 98014 | Carnation | 82 | B | 6 | $850K |
| 110 | 98028 | Kenmore | 82 | B | 0 | $870K |
| 111 | 98038 | Maple Valley | 78 | B | 4 | $714K |
| 112 | 98045 | North Bend | 78 | B | 4 | $846K |
| 113 | 98019 | Duvall | 77 | B | 1 | $747K |
| 114 | 98027 | Issaquah | 74 | B | 4 | $976K |
| 115 | 98065 | Snoqualmie | 74 | B | 3 | $890K |
| 116 | 98013 | Burton | 73 | B | 0 | — |
| 117 | 98039 | Medina | 73 | B | 0 | $2000K |
| 118 | 98050 | Preston | 73 | B | 0 | — |
| 119 | 98224 | Baring | 73 | B | 12 | $605K |
| 120 | 98025 | Hobart | 66 | C | 0 | — |
| 121 | 98082 | Mill Creek | 66 | C | 0 | — |
| 122 | 98047 | Pacific | 60 | C | 0 | $431K |
Recommended Buyer Guides for King County
Filtered against EPA monitoring data and CDC lead-exposure guidance, the guides below skip the generic catalog and connect directly to the contaminants and hazards on file here.
- Best Lead Paint Test Kits — 54.5% of homes built before 1978
Deep Dive Reports
Detailed analysis for King County, Washington
Overview
King County in Washington covers 122 ZIP codes with an average Home Safety Score of A (91/100).
105 of 122 ZIP codes have recorded EPA violations. 1 health-based violation have been documented.
← Back to Washington water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.