Would this work to get "cleaner" water?

If the situation does get bad enough to warrent any of the topics on this form its obvious that the water supply will probably by affected by all the chemicals that may find its way into it.

If rainwater is collected in a set of sealable containers and then hidden some where for later use would it be able to stay useable and a little cleaner then the water with the experimental chemical in it?

Also if some one hid a container of water like in the situation in the above question and no one found it how long would the water stay useable for before it begins to evaporate?

well its said that in certain areas its best to not collect the first few minutes of the rainfall because that when all the heavier pollutants will be falling (so you could end up having soot and otehr chemicals in ur water.

As far as the container goes I beleive if its a glass container it will keep the water indefinetely if its properly sealed lid.

But then again I geuss if there ar microbes you may be best to jsut collect the rainwater then boil it b4 use.