The Minnesota Pollution Control Agency says tests find bacterial levels are safe at Big Sandy Lake near McGregor.
The agency on Monday collected water samples at eight locations on the lake. Officials wanted to determine whether septic systems overwhelmed by recent flooding on Big Sandy have affected the lake's water quality.
The MPCA said Thursday that none of the test results indicated bacterial levels high enough to warn people against having contact with the water. No further testing is planned.
Big Sandy Lake is about eight miles north of McGregor.
No lakes or rivers in northeastern Minnesota are currently listed for high bacterial levels.