Fakeologist Forums

Boiling will kill bugs, bacteria, virus but will not remove solid contaminants.
My backup system has a home made pre filter made of gravel, sand and charcoal to get the worst out and prolong the life of my fine filters, followed by chemical treatment and then boiling before use.
The important thing is to have redundancy in whatever system you use and to test it before you need it.

Boiling will not remove chemicals and pesticides. You need multi stage filtration and chlorine purification.

Yes and no. Large parts of my filters I can make myself easily. Small stones, gravel and sand are the main components of my home made pre filters with activated charcoal being the most 'difficult' part to make. Using that to pre filter means that my 100,000 litre filters 'should' last much, much longer.
The chlorine is shelf stable in powder form (liquid bleach degrades over time) and is pretty cheap. I have a 10+ year supply based on a grid up and wasteful water usage amount.

Rain water collection is a good idea if you can. Filter through a Brita filter.