The alert to hospitals comes as the world marked International World Water Day.
Emerging small towns have been identified as a direct threat to water, sanitation and hygiene sustainability.
Figures show that Kenya’s per capita for water is dwindling rapidly and haphazard development can only strain water resources more; there has been an 80 per cent drop in the past 45 years.
In February, employees in at least four buildings in the city centre were warned not to drink or use the tap water.
This is after the water was found to be contaminated with sewerage, raising fears of a cholera outbreak.
A spot check by The Standard revealed that the managements of I&M, Pioneer, Post Bank and Rahena buildings were aware of the lurking danger.
A memo addressed to I&M staff implored workers to avoid using tap water. It, however, indicated that the issue was being resolved by the Nairobi City Water and Sewerage Company.