A total of 88 schools are expected to remain closed for at least a week in order to prevent students from coming in contact with contaminated water.
According to officials, approximately 10 million gallons of sulphuric acid spilled into the Bacanuchi River from the Buenavista Copper Mine in Cananea on August 7.
The spill turned the river orange. Dead cattle were found by the side of river and dead fish in the water.
Mexico's National Water Commission is monitoring the situation and noted that if toxicity levels continue to depreciate, the water emergency could be lifted as early as this week or early next week.
It is unclear what caused the leak.