They have no method to clean it well enough to drink it safely.
In rural areas, 87% of people have no access to safe water. In the cities, 27% cannot get clean water.
to clean or give water to the animals
The cities in the Indus Valley were very clean because of the meticulous way they were built in. The city's sanitation and waste water technologies had substantially developed.
They transported clean and fresh water to the cities like Rome.
If a lake is the only available, clean water, yes. Parrots will drink from any clean water source: streams, rives or lakes.
They brought water from one location into cities and towns.
sometimes water may be clean after boiling but not all
Contaminated water can spread many diseases, such as cholera.
Growing food and getting clean water for mega cities
Third world country water issues are that they don't have clean and easily available water. They have to travel miles sometimes to get it and it is not clean or healthy.
If there is no water available, you cannot wash your clothes in the washing machine. You will need access to water in order to properly clean your clothes.
There are many techniques are available to clean your carpet like vinegar and with some water solution.