Assumption County, Louisiana
6 ZIP codes · Avg score 62/100 · Grade C · Updated 2026-06-04
Covering 6 ZIP codes, Assumption County falls in the average tier for tap water safety — violations appear in a meaningful share of areas, and the data suggests quality depends heavily on which specific part of the county a household sits in.
How Assumption County Compares
How Assumption County Compares
Assumption County scores 9 points below the Louisiana state average (71/100) and 6 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-04
ZIP Code Risk Map
Water Quality Map: Assumption County, Louisiana
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 16.2 (asthma 10.6%, diabetes 16.7%)
Estimated additional annual cost per homeowner: $5,407, driven primarily by sea_level
Infrastructure: 0.342% avg pipe failure probability, 17% of ZIPs at high risk
68.2% of homes built before 1978 (lead paint era)
Violation History (2021–2025)
→ Stable trendEPA violation counts by year across Assumption County water systems. Health-based shown in red, total in blue.
Peak year: 2025 with 6 violations. Past 5 years: 11 total (11 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: $5,407
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
16,872 housing units in Assumption 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 Assumption County
Remediation costs are relatively manageable for most homeowners in Assumption 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 Assumption 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 Assumption County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | St Martin Water and Sewer Commission 1 | 2,262 | 4 |
| 2 | ASSUMPTION PARISH WW DISTRICT 1 | 21,366 | 4 |
| 3 | St Mary Parish Water Sewerage Commission 1 | 2,823 | 4 |
| 4 | Morgan City Water System | 12,703 | 4 |
| 5 | St Mary Parish W&s #2 Bayou Vista | 5,379 | 4 |
6 total water systems serve Assumption County.
All ZIP Codes in Assumption County
6 ZIP codes tracked in Assumption County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 70390 | Napoleonville | 85 | A | 0 | $152K |
| 2 | 70380 | Morgan City | 72 | B | 4 (3 health) | $138K |
| 3 | 70391 | Paincourtville | 60 | C | 0 | — |
| 4 | 70393 | Plattenville | 60 | C | 0 | $210K |
| 5 | 70372 | Labadieville | 52 | D | 0 | $144K |
| 6 | 70339 | Pierre Part | 42 | D | 0 | $163K |
Recommended Buyer Guides for Assumption County
Editorial-only picks, screened against the EPA detections on file.
- Best Lead Paint Test Kits — 68.2% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
Deep Dive Reports
Detailed analysis for Assumption County, Louisiana
Overview
Assumption County in Louisiana covers 6 ZIP codes with an average Home Safety Score of C (62/100).
1 of 6 ZIP codes have recorded EPA violations. 3 health-based violations have been documented.
← Back to Louisiana 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.