Water officials blamed aging infrastructure as the reason behind the decision to turn off drinking water at all Detroit Public Schools Community District schools less than a week before the start of the school year.

DPSCD superintendent Nikolai Vitti said the district made the dramatic move after initial testing results for 16 schools from earlier this year showed higher than acceptable levels for copper and/or lead at one or more water sources. The district didn’t release the data returned from the testing on Wednesday.

Vitti said “out of an abundance of caution and concern for the safety of our students and employees, I am turning off all drinking water in our schools until a deeper and broader analysis can be conducted to determine the long-term solutions for all schools.”

During the indefinite shutoff, the district will have bottled water provided by the Great Lakes Water