Knox County, Maine
21 ZIP codes · Avg score 83/100 · Grade B · Updated
ZipCheckup grade for Knox County: B.
This ZIP looks solid, with a few items worth a quick check.
Knox County's tap water quality puts it in the upper tier nationally; the 21 ZIP codes here record few health-based violations.
How Knox County Compares
How Knox County Compares
Knox County scores 18 points above the Maine state average (65/100) and 10 points above the national average (73/100).
Data: ZipCheckup Home Safety Score model 4.0.0; EPA SDWIS, UCMR 5, EPA radon zones, EPA AirData Last verified:
ZIP Code Risk Map
Water Quality Map: Knox County, Maine
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.2 (asthma 11.9%, diabetes 11.2%)
Estimated additional annual cost per homeowner: $1,218, driven primarily by sea_level
64.6% of homes built before 1978 (lead paint era)
Violation History (2021–2025)
↑ Worsening trendEPA violation counts by year across Knox County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 8 violations. Past 5 years: 19 total (19 health-based). Health-based violations are rising versus the prior 2-year window - worth closer monitoring.
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
Modeled area-level indicator, not a failure probability. Sources: Census ACS housing age, EPA DWINS infrastructure needs, EPA SDWIS violations, and EPA lead indicators.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $1,218
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
24,331 housing units in Knox 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 Knox County
Remediation costs are relatively manageable for most homeowners in Knox 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 Knox County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water systems serving Knox County
4 community water systems serving Knox County.
- B
- B
- B
- B
Systems with the most violations in Knox County
1 water system with recorded EPA violations.
- B
All ZIP Codes in Knox County
21 ZIP codes tracked in Knox County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 04841 | Rockland | 83 | B | 2 | $234K |
| 2 | 04843 | Camden | 83 | B | 2 | $486K |
| 3 | 04856 | Rockport | 83 | B | 2 | $415K |
| 4 | 04861 | Thomaston | 83 | B | 2 | $260K |
| 5 | 04863 | Vinalhaven | 83 | B | 0 | $436K |
| 6 | 04547 | Friendship | — | — | $265K | |
| 7 | 04563 | Cushing | — | — | $371K | |
| 8 | 04574 | Washington | — | — | $187K | |
| 9 | 04645 | Isle Au Haut | — | — | $663K | |
| 10 | 04847 | Hope | — | — | $302K | |
| 11 | 04850 | Lincolnville Center | — | — | — | |
| 12 | 04851 | Matinicus | — | — | $425K | |
| 13 | 04853 | North Haven | — | — | $405K | |
| 14 | 04854 | Owls Head | — | — | $332K | |
| 15 | 04855 | Port Clyde | — | — | $359K | |
| 16 | 04858 | South Thomaston | — | — | $305K | |
| 17 | 04859 | Spruce Head | — | — | $744K | |
| 18 | 04860 | Tenants Harbor | — | — | $310K | |
| 19 | 04862 | Union | — | — | $237K | |
| 20 | 04864 | Warren | — | — | 0 | $216K |
| 21 | 04865 | West Rockport | — | — | — |
Recommended Buyer Guides for Knox County
Where county records show a lead exceedance or pre-1978 housing concentration, lead-specific filters and test kits move toward the top of the list.
- Best Lead Paint Test Kits — 64.6% of homes built before 1978
Deep Dive Reports
Detailed analysis for Knox County, Maine
Overview
Knox County in Maine covers 21 tracked ZIP records with an average Home Safety Score of B (83/100) across 5 scored records.
4 of 6 ZIP codes with a reported violation count in the available EPA record have recorded EPA violations. The available record reports no health-based violations for this measured scope.
← Back to Maine Home Safety Profile
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- PFAS screening: EPA UCMR 5
- Radon zones: EPA Map of Radon Zones
- Air quality: EPA AirData annual AQI
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Reporting periods vary by source. Missing data is shown as unavailable, not as zero.