whenfires wrote:I have a few Saywer Minis to hand and my plan for water preps is for a blend of water butt (one possibly two), four 25L food grade water containers as well as some off-the-shelf bottled water. But I keep thinking of this stored water I already have. Because of showers, cleaning and so on, about 100L of the 300L gets used every day and is refilled from the cold main. So, depending on what kind of SHTF event occurred I would have quite fresh water in there in the short term. There are no lead pipes and both the copper tank and header tank are sealed so it is just a question of what contaminants are either already in the tanks or have been caused by the heating/cooling of the water.
Basically, It seems a lot of water to ignore
I'm pretty sure that it would be fine, if you've got no lead in your pipes and no dead pigeon in the tank then the water would probably be fine to drink, and you can always boil it to make sure, also most things like lead or heavy metal poisoning would only happen over time so even if there were heavy metal contamination in the water, you only have 300l in there and if it's not being refilled then it'll run out before you see any problems
It would likely be a fair bit cleaner than the water in a water butt, rain water is pretty clean on its way down (although can pick up some pollutants from the air) but your roof isn't clean, and it'll get washed into your water butt, but filtered or boiled it'd probably be ok too, certainly better than dehydration and then death!
I know that in dry areas where people routinely harvest rainwater from their roofs for drinking they have a special valve on the divertor that discards the first part of the flow, the first bit has most of the contamination in it and means your stored water is cleaner.
That is not dead which can eternal lie, and with strange aeons even death may die.