Cisterns
What was "Cistern Water"
In Israel, the rainy season is only five months long, stretching from November through March. Since fresh springs like those at En Gedi are rare, most ancient cities, towns, and even households used cisterns to catch and store rain runoff from rooftops, courtyards, and even streets.
Consequently, cistern water wasn't like the clean, fresh, flowing water of a spring. It was usually stale and dirty - perhaps even fouled by dead animals.
Furthermore, cisterns were dug by hand out of solid rock and were plastered so they would hold water. They needed constant care because the plaster tended to fall off, which allowed the precious water to leak out. When a cistern failed to hold water, it created a desperate situation for the people who depended on it.
Cisterns Were Used for More Than Water!
In addition, cisterns served as prisons (Jer. 38:6-13), symbolized prosperity (2 Kings 18:28-32), and served as hiding places (1 Sam. 12:6). Cisterns were built by kings as well as common people; they were used as tombs (Jer. 41:7-9), and also were used in teaching metaphors (Prov. 5:15-18).
