The Florida Department of Health is advising people not to swim or take part in other water-related activities at Hobe Sound Beach because of an increased risk of illness from enterococcus bacteria.

Tests completed Nov. 9 found that water quality at the Martin County beach did not meet the state’s recreational standard. The advisory will remain in place until bacteria levels fall below the accepted threshold, according to the department.

Martin County Ocean Rescue will fly a purple flag at the beach while the advisory is active. Current beach conditions can also be monitored at safebeachday.com, and state test results are available through the Florida Healthy Beaches Program.

Enterococci bacteria normally live in the intestinal tracts of people and animals. Higher concentrations can indicate fecal pollution, which the state says may come from stormwater runoff, pets, wildlife or human sewage.

Under the Department of Health’s water-quality scale, marine water is rated good at 0 to 35 enterococci per 100 milliliters, moderate at 36 to 70, and poor at 71 or more. The Healthy Beaches Program monitors water quality in Florida’s 31 coastal counties, with beaches generally tested every other week.