State officials will again begin monitoring water at state park beaches for high bacteria levels this week. Department of Natural Resources spokesperson Liz Shinall says they have a better handle on when a beach is a danger as last year they used E-P-A recommendations on closing beaches last year. This year Shinall says they’ll use five samples to determine if a beach should be closed, calculating the samples together to determine if the level meets EPA standards.She says they’ve discovered that one bad sample doesn’t mean the whole beach is bad.The D-N-R studies found that rainfall can cause bacteria levels to spike up, while good weather causes them to drop. This means water at a beach can show high levels after a rainfall, but quickly return to acceptable levels. Shindig says Iowa beaches are overall pretty safe.She says last year they found the 31 beaches sampled were safe 95-percent of the time. Shinall says you should use common sense when swimming in natural waters, such as not swimming right after a big rainfall.