Last week's heavy rain rendered five Wareham beaches unsuitable for swimming on August 25.

The North Boulevard, East Boulevard, Pinehurst, Forbes, and Indian Mound beaches were closed for about a day after a Barnstable County Water Quality Testing Laboratory analysis revealed that those beaches tested beyond the allowable tolerances for coliform bacteria levels.

Water samples were analyzed again on August 26, and the laboratory determined that the beaches met bacterial standards and were suitable for swimming once again. All Wareham beaches are currently open for swimming.

Seaweed is kicked to shore when the water gets rough, due to heavy rains or boats, said Health Agent Robert Ethier. Animals defecate in the weeds, and when heavy rainwater runs through catch basins and outfalls onto beaches, coliform bacteria enters the water, Ethier said.

Swimming at beaches with high coliform bacteria levels can cause serious health problems for very young, very old, or immune-compromised individuals.