Ka cika wannan jumla: Domin ana ɗiban ruwa daga famfunan ruwa kai tsaye daga ƙasa, yana da saurin gurɓacewa. Idan ba a tsabtace ruwan ba, zai iya sa mutum ya kamu da cututtuka na hanji ko kuma wasu cututtuka da ake samu daga ruwan. Wani sanannen yanayin shine
1854 Broad Street cutar kwalara ta barke. A lokacin ba a san yadda ake yada cutar kwalara ba, amma likita John Snow ya yi zargin gurɓataccen ruwa kuma ya cire makullin famfo na jama'a da ya yi zargin an cire shi; sai cutar ta ragu.