Exodus 7:24

And all the Egyptians digged round about the river for water to drink; for they could not drink of the water of the river.

All the Egyptians digged round about the river for water to drink. The polluted state of their river was a severe calamity, as the want of their favourite beverage, the Nile water, was a grievous privation. The only drinkable water that could be obtained during the continuance of the plague was dug out from subterranean springs among the sands.