Water tests at Christus St. Vincent Regional Medical Center have turned up hazardous levels of lead every year since 2011, sometimes exceeding the federal limit at which remediation is required by wide margins, state and federal records show. And while federal regulations require public water systems to treat and reduce lead levels that violate the standard in a timely manner, the hospital’s sampling record shows it had repeated violations of lead limits within some of the same 10 locations where it regularly tests the water for lead and copper.