The weather may say “summer,” but in most Iowa communities the public pool doesn’t open till Memorial Day. When it does, the state Health Department’s Mike Magnant says very strict rules will try to ensure that the water’s safe. He says in a public pool they have to test the water for chlorine levels and pH balance at least twice every day. The environmental engineer says the water’s only safe for children if they go to the pool with a grownup, as nationally, drowning is the number-one cause of death for kids under five. He says adult supervision is always a “must.” He says young children may be required to wear special diapers, so the water remains free from contamination that could make others sick.