The first plague is about to reach past the river itself. God tells Aharon to stretch the rod over rivers, trenches, canals, and every place for collecting their waters (Exodus 8:1 in the Targum's numbering, Exodus 7:19 in English Bibles). Targum Pseudo-Jonathan on Exodus 7:19 adds the final nail: there shall be blood in all the land of Mizraim, and in vessels of wood and in vessels of stone.
The meturgeman is walking the listener through an Egyptian household. The wooden bucket by the door. The stone jug in the cool corner of the kitchen. The clay basin beside the master's bed. Every container of water — already drawn, already stored, already trusted — turns the instant the rod is raised. The plague does not merely hit the source; it hits the supply.
This is precision meant to terrify. Even the water you thought was safe, the water you kept inside, the water that was no longer the Nile's — that too is blood. There is no cupboard in Egypt where the God of Israel cannot reach.
The takeaway: divine justice does not stop at the city wall or the front door. The oppressor cannot hoard safety. And for Israel watching from Goshen, the lesson is inverted — the God who can reach every vessel in Egypt can also reach every Jewish home in exile with blessing.