Sac County Lake Quality
Iowa, 2 lakes, average grade D (Poor)
Sac County has 2 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-wide average grade is D — water quality issues are persistent across most of the monitored basins. 1 lakes fall into the F bracket outright.
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. Arrowhead Lake (C) is the cleanest in the county.
Quick Answers for Sac County
Planning a trip? Check special fishing regulations for Arrowhead Lake — or check the official Iowa fishing regulations.
All Lakes in Sac County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Arrowhead Lake | C | 5.6 ft | - |
| 2 | Black Hawk Lake | F | 0.9 ft | - |
Other Counties in Iowa
See how Sac County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 15 states.
Where to stay near Sac County
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Source: EPA National Aquatic Resource Surveys, 2026.