countyscore

Best Water Quality Counties in Delaware

EPA drinking water health violations and safety grades Compare rankings across all 3 counties.

Average Water Quality Score
66/100
Top County
New Castle County
Counties Ranked
3

Top 10

#1
New Castle County
DE
86/100
#2
Kent County
DE
57/100
#3
Sussex County
DE
56/100

All Delaware Counties Ranked

#CountyWater Quality ScoreOverall Score
1New Castle County, DE
86
44.3
2Kent County, DE
56.8
44.2
3Sussex County, DE
55.6
50.4

Data Source

Water Quality data from WaterByCounty. See full details at WaterByCounty. Data updated February 2026.