More than 50 Maine beaches tested positive for potentially unsafe levels of fecal bacteria on at least one day in 2024, according to a new report.

The nationwide study published Monday by the Environment America Research and Policy Center also says 15 Maine beaches tested positive for potentially unsafe levels on more than 25% of the days they were tested.

Many of the beaches to reach that 25% mark were tested between 18 and 26 times in 2024. They include Goodies Beach in Rockport (48% of test days), Cape Neddick Beach in York (45%), Laite Beach in Camden (44%), Gooch’s Beach in Kennebunk (42%), Riverside Beach in Ogunquit (40%), Little Beach in Ogunquit (37%), and Ferry Beach in Scarborough (33%).

Mothers Beach in Kennebunk (23%), Goose Rocks Beach in Kennebunkport (22%) and Willard Beach in South Portland (21%) were some that fell just short of that threshold.

The 51 beaches in Maine to have tested positive for potentially unsafe contamination levels for at least one day in 2024 are among 1,930 across the country. A total of 3,187 were tested nationwide as part of the study, with 65 of them in Maine.

Aging and deteriorating sewage systems, and runoff from development are the main contributors to contamination levels, the report said.

“Sewage is a particularly dangerous threat to beach safety because it contains bacteria, viruses and parasites that are prone to cause disease in humans,” the report states.

Impacts from development compound the issue.

“The addition of impervious surfaces — such as parking lots, roads and larger homes — increases the flow of polluted stormwater into our rivers, bays and coastal waters,” the report says. “Paving over wetlands or forests that had once absorbed rainfall and filtered pollution makes this problem worse.”

Another cause for unsafe contamination levels is animal waste, the report said, whether that be on a beach itself, or by rivers and streams that eventually feed into the ocean.

“Despite some progress, water pollution remains a persistent threat to beachgoers and the ecosystems that support them,” the report states. “Contaminated runoff, aging sewage systems and agricultural waste continue to close beaches and endanger public health.”