WATERLOO — Many people in Iowa’s jails — as many as a third — do not belong there, law enforcement officials say.Too many are jailed when what they need is mental health care.The scenario has become all too common: A person with a mental illness does not get needed treatment or declines to take prescribed medication, then behaves in a way that gets law enforcement involved.“So, what we’ve got now, is the jails have become the mental health institutions for the state,” said John Miller, a Black Hawk County supervisor.The state’s mental health care system is plagued, law enforcement officials and mental health advocates agree, by a lack of access because of a shortage of beds and a lack of available mental health professionals.