I’m going to have to wave the BS flag on this statement. This is EXACTLY the issue that occurred in Flint. Changing water source changed pH, thus accelerating leaching of heavy metals from customer plumbing.
“The city of Phoenix is responsible for providing high quality drinking water, but cannot control the variety of materials used in plumbing components,” according to the report. “When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your tap water for 30 seconds to two minutes before using water for drinking or cooking.”