Skip to main content
LakeQuality
F

Washington County Lake Quality

Wisconsin, 1 lakes, average grade F (Very Poor)

Washington County has 1 graded lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. The county average is F — the most-stressed bracket in our rubric. Most monitored lakes here show persistent nutrient loading and algal pressure.

Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Nashville City Lake (F) is the cleanest in the county.

Loading map…

All Lakes in Washington County

RankLakeGradeClarityMax DepthPhosphorus
1Nashville City LakeF1.3 ft-517 µg/L

Source: EPA National Aquatic Resource Surveys, 2026.