Dorchester County, District of Columbia
1 ZIP code · Avg score 72/100 · Grade B · Updated 2026-06-04
In recent assessments, Dorchester County's 1 ZIP code record strong, consistent water safety outcomes.
How Dorchester County Compares
How Dorchester County Compares
Dorchester County scores 4 points above the District of Columbia state average (68/100) and 4 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-04
Key Risk Factors
Health risk index: 12.6 (asthma 9.6%, diabetes 12.8%)
Estimated additional annual cost per homeowner: $1,780, driven primarily by sea_level
Infrastructure: 0.37% avg pipe failure probability
Violation History (2022–2025)
→ Stable trendEPA violation counts by year across Dorchester County water systems. Health-based shown in red, total in blue.
Peak year: 2025 with 3 violations. Past 5 years: 5 total (5 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: $1,780
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Health Outcomes vs National Average
CDC PLACES data for Dorchester County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 4 systems in Dorchester County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | D.c. Water and Sewer Authority | 632,323 | 33 |
| 2 | Joint Base Anacostia - Bolling | 19,312 | 33 |
| 3 | Naval Station Washington - Wny | 15,690 | 33 |
| 4 | Washington Aqueduct Division. | — | 33 |
All ZIP Codes in Dorchester County
1 ZIP code tracked in Dorchester County.
| # | ZIP Code | City | Safety Score | Grade | Violations |
|---|---|---|---|---|---|
| 1 | 20405 | Washington | 72 | B | 33 (6 health) |
Recommended Buyer Guides for Dorchester County
Where county records show a lead exceedance or pre-1978 housing concentration, lead-specific filters and test kits move toward the top of the list.
- 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
Overview
Dorchester County in District of Columbia covers 1 ZIP code with an average Home Safety Score of B (72/100).
1 of 1 ZIP code have recorded EPA violations. 6 health-based violations have been documented.
← Back to District of Columbia water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
Updated daily.