Exodus 7:23-25

New Revised Standard Version, Anglicised

²³ Pharaoh turned and went into his house, and he did not take even this to heart. ²⁴ And all the Egyptians had to dig along the Nile for water to drink, for they could not drink the water of the river.

²⁵ Seven days passed after the Lord had struck the Nile.