Merrimack County, New Hampshire
31 ZIP codes · Avg score 78/100 · Grade B · Updated
ZipCheckup grade for Merrimack County: B.
This ZIP looks solid, with a few items worth a quick check.
Based on current EPA data, Merrimack County's 31 ZIP codes maintain an above-average drinking water safety record.
How Merrimack County Compares
How Merrimack County Compares
Merrimack County scores 4 points above the New Hampshire state average (74/100) and 5 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: Merrimack County, New Hampshire
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 11.8 (asthma 11%, diabetes 9.1%)
Estimated additional annual cost per homeowner: $1,660, driven primarily by flood
64.1% of homes built before 1978 (lead paint era)
Violation History (2021–2025)
↑ Worsening trendEPA violation counts by year across Merrimack County water systems. Health-based shown in red, total in blue.
Peak year: 2025 with 24 violations. Past 5 years: 55 total (55 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: $1,660
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
65,348 housing units in Merrimack 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 Merrimack County
Remediation costs are relatively manageable for most homeowners in Merrimack 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 Merrimack County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water systems serving Merrimack County
8 community water systems serving Merrimack County.
- C
- B
- B
- C
- C
- B
Show all 8 water systems
- B
16 total water systems serve Merrimack County.
Systems with the most violations in Merrimack County
3 water systems with recorded EPA violations.
- B
- C
All ZIP Codes in Merrimack County
31 ZIP codes tracked in Merrimack County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 03235 | Franklin | 83 | B | 0 | $245K |
| 2 | 03257 | New London | 83 | B | 0 | $469K |
| 3 | 03301 | Concord | 83 | B | 0 | $344K |
| 4 | 03303 | Concord | 83 | B | 0 | $274K |
| 5 | 03229 | Contoocook | 81 | B | 21 (20 health) | $441K |
| 6 | 03106 | Hooksett | 67 | C | 0 | $372K |
| 7 | 03275 | Suncook | 66 | C | 1 | $309K |
| 8 | 03034 | Candia | — | — | $395K | |
| 9 | 03046 | Dunbarton | — | — | $437K | |
| 10 | 03216 | Andover | — | — | $332K | |
| 11 | 03221 | Bradford | — | — | $302K | |
| 12 | 03224 | Canterbury | — | — | $410K | |
| 13 | 03230 | Danbury | — | — | $213K | |
| 14 | 03231 | East Andover | — | — | — | |
| 15 | 03233 | Elkins | — | — | $397K | |
| 16 | 03234 | Epsom | — | — | 0 | $298K |
| 17 | 03242 | Henniker | — | — | 0 | $318K |
| 18 | 03243 | Hill | — | — | $243K | |
| 19 | 03255 | Newbury | — | — | $441K | |
| 20 | 03258 | Chichester | — | — | $360K | |
| 21 | 03260 | North Sutton | — | — | $297K | |
| 22 | 03263 | Pittsfield | — | — | 0 | $271K |
| 23 | 03268 | Salisbury | — | — | $313K | |
| 24 | 03272 | South Newbury | — | — | — | |
| 25 | 03273 | South Sutton | — | — | $277K | |
| 26 | 03278 | Warner | — | — | $323K | |
| 27 | 03287 | Wilmot | — | — | $373K | |
| 28 | 03302 | Concord | — | — | — | |
| 29 | 03304 | Bow | — | — | 3 (3 health) | $444K |
| 30 | 03305 | Concord | — | — | — | |
| 31 | 03307 | Loudon | — | — | $316K |
Recommended Buyer Guides for Merrimack County
Below: editorial picks, no sponsored placements.
- Best Lead Paint Test Kits — 64.1% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Deep Dive Reports
Detailed analysis for Merrimack County, New Hampshire
Overview
Merrimack County in New Hampshire covers 31 tracked ZIP records with an average Home Safety Score of B (78/100) across 7 scored records.
3 of 11 ZIP codes with a reported violation count in the available EPA record have recorded EPA violations. 23 health-based violations appear in the available health breakdown.
← Back to New Hampshire 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.