Out of 88 Seattle schools recently tested, officials have found lead exceeding federal government standards in drinking water fountains at 70 of them.
The Seattle Post-Intelligencer has reported that district-wide tests were conducted in recent months are nearly concluded.
Findings show that at some schools, toxic concentrations in drinking water are far above the federal threshold.
The EPA standard is 20 parts per billion. But at 19 schools, more than half the fountains had more lead in the water than 20 parts per billion.
The tests were made on the first water from the fountain after sitting in pipes for eight hours or more.
A second test after pipes were cleared also showed lead in some fountain water.