Nantucket County, Massachusetts
4 ZIP codes · Avg score 67/100 · Grade C · Updated 2026-06-03
For most households in Nantucket County, the 4 tracked ZIP codes show adequate but uneven water quality.
How Nantucket County Compares
How Nantucket County Compares
Nantucket County scores 1 points above the Massachusetts state average (66/100) and 1 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
Key Risk Factors
Health risk index: 10.4 (asthma 10.9%, diabetes 8.6%)
Estimated additional annual cost per homeowner: $3,675, driven primarily by sea_level
Infrastructure: 0.435% avg pipe failure probability, 75% of ZIPs at high risk
64.8% of homes built before 1978 (lead paint era)
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: $3,675
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
19,591 housing units in Nantucket 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 Nantucket County
Remediation costs are relatively manageable for most homeowners in Nantucket 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 Nantucket County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 4 systems in Nantucket County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Wannacomet Water Company | 27,703 | 12 |
| 2 | Siasconset Water Department | 3,000 | 12 |
| 3 | City of New Bedford Dpi | 101,079 | 0 |
| 4 | Brookside Mobile Home Park | 67 | 0 |
All ZIP Codes in Nantucket County
4 ZIP codes tracked in Nantucket County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 2746 | New Bedford | 83 | B | 0 | $324K |
| 2 | 2584 | Nantucket | 74 | B | 6 | — |
| 3 | 2554 | Nantucket | 59 | C | 6 | $1386K |
| 4 | 2564 | Siasconset | 50 | D | 0 | $1547K |
Recommended Buyer Guides for Nantucket County
Filtered against federal data, fitted to local risks.
- Best Lead Paint Test Kits — 64.8% of homes built before 1978
Overview
Nantucket County in Massachusetts covers 4 ZIP codes with an average Home Safety Score of C (67/100).
2 of 4 ZIP codes have recorded EPA violations. All violations are monitoring/reporting type.
← Back to Massachusetts 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.