Activated charcoal tends to remove certain classes of chemicals fairly well. Chlorine is one, plus a lot of organic chemicals. But that leaves a lot of things that activated charcoal does not filter at all. I mean, take something simple like sodium. Activated charcoal does not filter sodium, so if you had a home water softening system on your tap that added sodium to the water, the sodium concentration would pass through the activated charcoal filter in your Brita pitcher unchanged.

Anyway, my point is, be careful not to just assume that just because of the extensive list (which I just skimmed on the Berkey website), that this filter will make pool water safe. "Safer" as you point out, maybe, but there is a real possibility that it could also completely miss pool chemicals that would make you sick if you're drinking gallons of it long term.

Actually, that got me to thinking. If you already have an idea early on in some crisis that you're likely to completely run out of your stored water with little hope of resupply and would be forced to start drinking pool water eventually, it would actually make sense to start mixing drinking and pool water early on to dilute the chemicals. Again, I'm talking emergency situation here, but I think the dilution would help to lessen the impact of drinking straight pool water, like maybe GI upset. I guess another possibility is that you find yourself needing to support a lot more people than you were planning for. Again, to stretch your water supply, dilution early on might be something to consider.

This idea goes against everything that emergency managers tell people about pool water, just so everyone is clear. But I'm just raising the point for people to think about in case they're faced with such a choice.