Johnston County, North Carolina
12 ZIP codes · Avg score 82/100 · Grade B · Updated 2026-06-03
In current tracking cycles, Johnston County — spanning 12 ZIP codes — records above-average water quality outcomes; the county's compliance history over recent years shows few departures from federal standards.
How Johnston County Compares
How Johnston County Compares
Johnston County scores 9 points above the North Carolina state average (73/100) and 14 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Johnston County, North Carolina
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 12.6 (asthma 10.8%, diabetes 11.6%)
Estimated additional annual cost per homeowner: $1,335, driven primarily by flood
Infrastructure: 0.35% avg pipe failure probability, 9% of ZIPs at high risk
42.8% of homes built before 1978 (lead paint era)
Violation History (2022–2025)
↑ Worsening trendEPA violation counts by year across Johnston County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 24 violations. Past 5 years: 40 total (40 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
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $1,335
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
70,124 housing units in Johnston 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 Johnston County
Remediation costs are relatively manageable for most homeowners in Johnston 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 Johnston 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 Johnston County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Micro, Town of | 470 | 35 |
| 2 | Pine Level, Town of | 2,413 | 34 |
| 3 | Buffalo Creek S/d | 721 | 33 |
| 4 | Smithfield, Town of | 12,900 | 28 |
| 5 | Wayne Water Districts | 39,403 | 24 |
28 total water systems serve Johnston County.
All ZIP Codes in Johnston County
12 ZIP codes tracked in Johnston County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 27504 | Benson | 95 | A | 1 | $217K |
| 2 | 27568 | Pine Level | 92 | A | 14 (3 health) | $233K |
| 3 | 27524 | Four Oaks | 86 | A | 7 (4 health) | $211K |
| 4 | 27576 | Selma | 86 | A | 11 (4 health) | $178K |
| 5 | 27528 | Clayton | 85 | A | 4 | — |
| 6 | 27555 | Micro | 85 | A | 16 (7 health) | $213K |
| 7 | 27527 | Clayton | 84 | B | 4 | $361K |
| 8 | 27520 | Clayton | 79 | B | 4 | $282K |
| 9 | 27577 | Smithfield | 77 | B | 6 (1 health) | $230K |
| 10 | 27569 | Princeton | 76 | B | 9 (2 health) | $194K |
| 11 | 27542 | Kenly | 68 | C | 8 (7 health) | $181K |
| 12 | 27593 | Wilsons Mills | 66 | C | 0 | — |
Recommended Buyer Guides for Johnston County
Four sources — EPA, NSF, FEMA, CDC — drive the match.
- 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 Johnston County, North Carolina
Overview
Johnston County in North Carolina covers 12 ZIP codes with an average Home Safety Score of B (82/100).
11 of 12 ZIP codes have recorded EPA violations. 28 health-based violations have been documented.
← Back to North Carolina 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.