Make your Home Green

What is the easiest and cheapest way to filter rain water for drinking?

Hi, I’m doing a school project and I’d like to know what options are there in terms of rainwater harvesting/conservation and filtering for drinking.
The water tank/container must not be in the ground as I do not want to use any form of gray water system (or any other system).
I want to find the cheapest and easiest way of conserving and filtering water so that it would be drinkable in rural areas, as the project I am doing aims to convert a storage container into a classroom and would need to be portable.
What options do I have in this scenario?

You have several options, but you need to keep in mind that filtration DOES NOT get bacteria or some contaminants unless you invest in quite expensive RO/DI and carbon filtration systems. Nor will filtration handle acidity or alkalinity.

As drinking is the goal, not irrigation, I suggest you do this in two stages: Collect the water in a covered container made of impervious materials (plastic or stainless steel, not wood, aluminum or mild steel), then run it through a solar still (linked below) for purification. No chemicals, pumps, fancy filters or other items to add cost or complexity.

Pt. 2 Cooking 31 minute Biogas Meal and Schmutzdecke water filter