Delaware County, Ohio
9 ZIP codes · Avg score 57/100 · Grade C · Updated 2026-06-03
Delaware County shows moderate water quality across its 9 ZIP codes — some areas carry violations worth monitoring.
How Delaware County Compares
How Delaware County Compares
Delaware County scores 3 points below the Ohio state average (60/100) and 11 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Delaware County, Ohio
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 12 (asthma 9.8%, diabetes 11%)
Estimated additional annual cost per homeowner: $1,092, driven primarily by sea_level
Infrastructure: 0.286% avg pipe failure probability, 13% of ZIPs at high risk
37.4% of homes built before 1978 (lead paint era)
Violation History (2022–2024)
→ Stable trendEPA violation counts by year across Delaware County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 2 violations. Past 5 years: 3 total (3 health-based).
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: $1,092
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
57,279 housing units in Delaware 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 Delaware County
Remediation costs are relatively manageable for most homeowners in Delaware 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 Delaware 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 Delaware County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Del-Company Water Company, Inc. | 150,000 | 16 |
| 2 | COLUMBUS PUBLIC WATER SYSTEM | 1,305,946 | 15 |
| 3 | WESTERVILLE CITY PWS | 39,000 | 15 |
| 4 | Picket Fences Mhp | 27 | 7 |
| 5 | London City Public Water System | 10,256 | 7 |
18 total water systems serve Delaware County.
All ZIP Codes in Delaware County
9 ZIP codes tracked in Delaware County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 43082 | Westerville | 69 | C | 1 (1 health) | $433K |
| 2 | 43003 | Ashley | 68 | C | 1 | $198K |
| 3 | 43015 | Delaware | 65 | C | 0 | $312K |
| 4 | 43240 | Columbus | 64 | C | 7 (2 health) | $290K |
| 5 | 43035 | Lewis Center | 62 | C | 7 | $423K |
| 6 | 43061 | Ostrander | 53 | D | 0 | $387K |
| 7 | 43334 | Marengo | 53 | D | 0 | $246K |
| 8 | 43032 | Kilbourne | 40 | D | 0 | — |
| 9 | 43356 | Waldo | 40 | D | 0 | $263K |
Recommended Buyer Guides for Delaware County
Independent picks. EPA-grounded. Matched here.
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
Deep Dive Reports
Detailed analysis for Delaware County, Ohio
Overview
Delaware County in Ohio covers 9 ZIP codes with an average Home Safety Score of C (57/100).
4 of 9 ZIP codes have recorded EPA violations. 3 health-based violations have been documented.
← Back to Ohio 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.