Coos County, New Hampshire
16 ZIP codes · Avg score 67/100 · Grade C · Updated 2026-06-04
Water monitoring across Coos County's 16 ZIP codes paints a mid-range picture — solid compliance in some zones, documented concerns in others; most violations on record are concentrated in specific prior years rather than spread evenly across the full compliance history, and the overall county grade has held steady in the middle tier without major shifts in either direction.
How Coos County Compares
How Coos County Compares
Coos County scores 3 points above the New Hampshire state average (64/100) and 1 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-04
ZIP Code Risk Map
Water Quality Map: Coos 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: 14.6 (asthma 11.5%, diabetes 13%)
Estimated additional annual cost per homeowner: $922, driven primarily by energy_code_gap
Infrastructure: 0.388% avg pipe failure probability, 33% of ZIPs at high risk
66.7% 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: $922
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
20,904 housing units in Coos 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 Coos County
Remediation costs are relatively manageable for most homeowners in Coos 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 Coos 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 Coos County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Colebrook Water Works | 1,300 | 2 |
| 2 | Berlin Water Works | 9,575 | 1 |
| 3 | LANCASTER WATER DEPT | 2,450 | 1 |
| 4 | Errol Water Works/west | 183 | 1 |
| 5 | WHITEFIELD WATER | 1,640 | 1 |
11 total water systems serve Coos County.
All ZIP Codes in Coos County
16 ZIP codes tracked in Coos County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 3570 | Berlin | 83 | B | 1 | $114K |
| 2 | 3579 | Errol | 75 | B | 1 | $251K |
| 3 | 3597 | West Stewartstown | 75 | B | 0 | — |
| 4 | 3576 | Colebrook | 74 | B | 2 | $187K |
| 5 | 3598 | Whitefield | 74 | B | 1 (1 health) | $205K |
| 6 | 3588 | Milan | 72 | B | 1 | $234K |
| 7 | 3592 | Pittsburg | 72 | B | 0 | $253K |
| 8 | 3595 | Twin Mountain | 72 | B | 0 | $229K |
| 9 | 3581 | Gorham | 70 | B | 0 | $156K |
| 10 | 3584 | Lancaster | 70 | B | 0 | $197K |
| 11 | 3575 | Bretton Woods | 63 | C | 0 | — |
| 12 | 3582 | Groveton | 55 | C | 0 | $117K |
| 13 | 3590 | North Stratford | 55 | C | 0 | $170K |
| 14 | 3583 | Jefferson | 53 | D | 0 | $309K |
| 15 | 3589 | Mount Washington | 53 | D | 0 | — |
| 16 | 3593 | Randolph | 53 | D | 0 | $300K |
Recommended Buyer Guides for Coos County
While many sites publish identical guide lists across every county they cover, the selection here changes by location — driven by the EPA, NSF, FEMA, and CDC datasets that describe the actual conditions documented for this jurisdiction in the federal record.
- Best Lead Paint Test Kits — 66.7% of homes built before 1978
Deep Dive Reports
Detailed analysis for Coos County, New Hampshire
Overview
Coos County in New Hampshire covers 16 ZIP codes with an average Home Safety Score of C (67/100).
5 of 16 ZIP codes have recorded EPA violations. 1 health-based violation have been documented.
← Back to New Hampshire 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.