Schools throughout the San Diego Unified School District and in surrounding communities began testing for lead in their drinking water on April 14. A majority of those examined so far have tested positive for elevated levels of lead in their water; at least eight schools have exceeded the minimum threshold for lead in water set by the state of California and will require immediate action.
At present, the US Environmental Protection Agency recommends schools shut off water facilities when results show 20 parts per billion (ppb) or greater of lead. However, as of January of this year the California State Water Resources Control Board mandated new regulations that lead in water cannot exceed 15 ppb and school sites may receive free testing by any request from a school official.
— source wsws.org