COUNTY REPORT OK

Delaware County, Oklahoma

10 ZIP codes · Avg score 62/100 · Grade C · Updated 2026-06-03

Monitoring figures for Delaware County indicate average water quality overall — some ZIP codes among the 10 tracked have recorded health-based violations, while others operate cleanly, making individual ZIP-level data the most actionable reference point.

How Delaware County Compares

Delaware County62/100
Oklahoma avg79/100
National avg68/100

How Delaware County Compares

C
County Grade
62/100
Avg Safety Score
10
ZIP Codes
32
Water Systems

Delaware County scores 17 points below the Oklahoma state average (79/100) and 6 points below the national average (68/100).

Data: EPA SDWIS Last verified: 2026-06-03

C
County Grade
62
Avg Safety Score
10
ZIP Codes
Best ZIP: 74342 (74/100)
Lowest ZIP: 74359 (53/100)
$126K
Median Home Value
$1,740
Avg Remediation (138% of home value)

ZIP Code Risk Map

Water Quality Map: Delaware County, Oklahoma

Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.

A B C D F

Key Risk Factors

Health risk index: 16.8 (asthma 12.2%, diabetes 16.5%)

Estimated additional annual cost per homeowner: $1,064, driven primarily by flood

Infrastructure: 0.38% avg pipe failure probability, 40% of ZIPs at high risk

53.8% of homes built before 1978 (lead paint era)

Violation History (2021–2025)

↑ Worsening trend

EPA violation counts by year across Delaware County water systems. Health-based shown in red, total in blue.

2021
3 (3 health)
2022
7 (7 health)
2023
12 (12 health)
2024
51 (51 health)
2025
8 (8 health)

Peak year: 2024 with 51 violations. Past 5 years: 81 total (81 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

Asthma 12.2% (national: 8.9%)
Diabetes 16.5% (national: 10.5%)
Obesity 38.3% (national: 32.4%)

Black markers indicate national averages. Source: CDC PLACES, Census ACS.

Infrastructure Overview

1986
Median Build Year
53.8%
Pre-1978 Housing
38%
Pipe Failure Probability
40%
ZIPs at High Infra Risk
Moderate
Lead Pipe Risk

Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.

Compound Risk Breakdown

Estimated additional annual cost per homeowner: $1,064

Flood $540/yr
Wildfire $300/yr
Water / Lead $125/yr

Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).

Housing Age Distribution

24,838 housing units in Delaware County

Pre-1940 4%
1940–1959 8%
1960–1979 27%
1980–1999 36%
2000+ 25%

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

$126K
Median Home Value
$1,740
Est. Remediation Cost
1.4%
of Home Value
Remediation as % of home value low burden

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

Asthma 12.2% (US avg: 8.9%)
Diabetes 16.5% (US avg: 11%)
Obesity 38.3% (US avg: 32.4%)

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 Hickory Meadows 157 149
2 Holiday Shores Prop Assn 136 149
3 Grove Municipal Services Authority 7,311 135
4 Seneca-cayuga Nation 400 116
5 Lakewood Village 293 116

32 total water systems serve Delaware County.

All ZIP Codes in Delaware County

10 ZIP codes tracked in Delaware County.

# ZIP Code City Safety Score Grade Violations Home Value
1 74342 Eucha 74 B 2 $128K
2 74338 Colcord 68 C 26 (2 health) $117K
3 74368 Twin Oaks 67 C 10 (1 health)
4 74347 Kansas 64 C 18 (5 health) $94K
5 74364 Rose 63 C 0 $152K
6 74345 Grove 62 C 58 (3 health)
7 74344 Grove 61 C 58 (3 health) $207K
8 74346 Jay 58 C 19 (11 health) $125K
9 74331 Afton 53 D 33 (8 health) $180K
10 74359 Oaks 53 D 0 $68K

Recommended Buyer Guides for Delaware County

Eight risk categories drive the selection — PFAS exceedance, lead above EPA action level, pre-1978 housing share, EPA Radon Zone 1, flood-top-risk, wildfire-top-risk, multi-contaminant load, and a baseline fallback — and each category maps to a specific buyer-guide track that surfaces when the county data hits its threshold for that hazard signal.

Overview

Delaware County in Oklahoma covers 10 ZIP codes with an average Home Safety Score of C (62/100).

8 of 10 ZIP codes have recorded EPA violations. 33 health-based violations have been documented.

← Back to Oklahoma water quality report

Data Sources

Updated daily.

Frequently Asked Questions

Is water safe in Delaware County?
Delaware County receives a grade of C. Some ZIP codes have recorded violations and residents in affected areas may want to test their water.
How many water systems serve Delaware County?
Delaware County is served by 32 public water systems that supply drinking water to residents across 10 ZIP codes.
What is the biggest environmental risk in Delaware County?
The primary environmental risk factor in Delaware County is flood. This contributes to an estimated additional annual cost of $1,064 per homeowner.
How old are homes in Delaware County?
The median home build year in Delaware County is 1986. 53.8% of homes were built before 1978, which means they may contain lead-based paint and older plumbing materials.
How does Delaware County compare to Oklahoma?
Delaware County has an average water safety score of 62/100, which is below the Oklahoma state average of 79/100.

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