Classicly

The sources of contaminated drinking-water are very numerous, and may affect the water at its source, in its flow, in its reservoir, or during distribution. When stored in houses, it is especially exposed to risk, and this is the most important argument in favour of constant service. Cistern stowage lessens the risks incidental to intermissions; but at the same time the success of this plan entirely depends upon the receptacle being properly made and frequently cleansed. An eminent physician told the writer that he believed typhoid fever often originated from the stagnant water in dirty cisterns being used for drinking purposes.