Polluted water can cause health problems

In smaller towns and cities the water is available for a limited time and it is stored in overhead tanks.
In some cases, there are pollutants in the tank and this can make drinking the water a major health risk. In some cases, people residing in the house suffer from diarrhea if they drink even a small amount of the tank water. Additionally in some cases, loose motion can also cause insomnia at night.
So even for brushing teeth mineral water is required, which is inconvenient if a person is not well and cannot go out to purchase the mineral water.