Exodus 7:19

The waters of Egypt consist of the main stream of the Nile; its branches; canals derived from it; natural lakes, pools, or ponds, either left by the inundation or anticipative of it, being derived by percolation from the main stream; and artificial reservoirs of a larger or smaller size in gardens, courts, and houses. There is no other stream but the Nile in the whole country; and there are no natural springs, fountains, or brooks. Water may, however, at all times, and in all parts of the Nile Valley, be obtained by digging wells; but, as the soil is impregnated with nitre, the well water is highly unpalatable. It is generally allowed that the author of Exodus shows in the present verse, coupled with Exodus 7:24, a very exact knowledge of the Egyptian water system.

Vessels of wood, and vessels of stone. — It was usual to store the Nile water in tanks or cisterns within the houses, in order that it might deposit its sediment. These tanks or cisterns, which existed in all the houses of the better class, were either of wood or stone.