Elevated bacteria levels in the water have shut down or partially closed 71 Long Island beaches Wednesday.

Suffolk County Health Commissioner Dr. Brian Harper says the contamination stemmed from heavy rain that pounded Long Island overnight. According to Harper, the 1.5 inches of rain that fell in a two-hour time period caused a substantial amount of storm water runoff into the ocean. He says this water can carry animal feces and other bacteria that can cause gastrointestinal diseases.

Many residents say they know to stay out of the water after heavy storms, but wish there were signs warning beachgoers. Harper says it is possible some may have gotten sick before the beaches were closed, but is hopeful the shutdown came in time.

Officials say the water will be tested Thursday morning and a decision will be made when to re-open the beaches.

Related Information: List of beach closings