Williams County Lake Quality

Williams County's 25 monitored lakes fall in the moderate-density bracket for North Dakota. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. 6 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.

The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Kota Ray Dam Lake (B); the most-stressed is Epping-Springbrook Dam-Deepest Lake (D).