Marshall County, Oklahoma
3 ZIP codes · Avg score 79/100 · Grade B · Updated 2026-06-03
Unlike many counties its size, Marshall County keeps violation rates low — all 3 ZIP codes score at or above the state average for tap water safety, with no systemic concerns flagged in the current data set.
How Marshall County Compares
How Marshall County Compares
Marshall County scores 0 points above the Oklahoma state average (79/100) and 11 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
Key Risk Factors
Health risk index: 16.1 (asthma 11.6%, diabetes 15.7%)
Estimated additional annual cost per homeowner: $810, driven primarily by wildfire
Infrastructure: 0.37% avg pipe failure probability, 33% of ZIPs at high risk
59.3% of homes built before 1978 (lead paint era)
Violation History (2022–2025)
↑ Worsening trendEPA violation counts by year across Marshall County water systems. Health-based shown in red, total in blue.
Peak year: 2025 with 21 violations. Past 5 years: 42 total (42 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: $810
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
8,854 housing units in Marshall 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 Marshall County
Remediation costs are relatively manageable for most homeowners in Marshall 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 Marshall 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 Marshall County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Marshall County Rural Water District #2 | 17,587 | 33 |
| 2 | Oakview Water Corporation | 925 | 33 |
| 3 | Cardinal Hill Subdivision | 475 | 33 |
| 4 | Madill | 3,410 | 29 |
| 5 | Oakland Pwa | 1,050 | 29 |
7 total water systems serve Marshall County.
All ZIP Codes in Marshall County
3 ZIP codes tracked in Marshall County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 73439 | Kingston | 94 | A | 4 (1 health) | $146K |
| 2 | 73440 | Lebanon | 73 | B | 0 | $172K |
| 3 | 73446 | Madill | 70 | B | 29 (24 health) | $123K |
Recommended Buyer Guides for Marshall County
Editorial methodology pairs each documented risk in this county with the buyer category that addresses it, drawing on water-quality detections, housing-stock lead exposure, EPA Radon Zone designation, and FEMA flood and wildfire ratings. NSF-certified options surface where applicable, and products that match the specific contaminant take priority.
- Best Lead Paint Test Kits — 59.3% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best HEPA Air Purifiers for Wildfire Smoke — Wildfire is the top compound risk factor
Overview
Marshall County in Oklahoma covers 3 ZIP codes with an average Home Safety Score of B (79/100).
2 of 3 ZIP codes have recorded EPA violations. 25 health-based violations have been documented.
← Back to Oklahoma 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.