Would filtratiton alone provide enough protection against disease?

Question

In a closed system where water used for drinking, cleaning, cooking and sanitary purposes is collected, treated with bacteria, allowed to settle and filtered through osmotic, activated charcoal and sand and gravel, would any viruses, bacteria or other disease passed into the system from other users be adequatedly removed before the water was reused or would chlorine be necessary?

Answer 1

Filtration alone is not enough

However, in my opinion, you shouldnt use chlorine since its more on large scale water distribution and having not so good knowledge of its accurate proportion can lead to toxicity

For me the best way to kill the bacteria is to do boiling after the filtration

Answer 2

Chlorine would also be necessary, and could then be trmoved by the other filters.