When schools officials began to find lead in drinking water at several San Diego schools in 2016, parents from across the region scrambled to understand the danger posed to their children by the toxic metal. At the time, we thought the lead was coming from inside schools because the city of San Diego sounded certain that its pipes were no longer made of lead. But it turns out, as we reported last week along with NBC San Diego, the city does not know what 192,000 of its water pipes are made of. Nor does it know what 16,000 pipe fittings are made of.