Thanks everyone. I did have plans for a 'grit tank' at the head of the line as well as an initial large diameter pipe to catch the very first water with a plug for easy dumping. The shed I'm planning on putting the system on should be reasonably free of other... material as there are no convienent nesting spots above it. And it flies the American flag, between the lack of a good stopping point and the flapping of the cloth the birds seem to not care to land on it.
My thought would be that the last barrel in the line would be the cleanest water. The first tank could be used for cleaning etc and start with the last for drinking and work our way back up the line in a waterless situation.
We have enough water stored inside the house to get by for a few weeks with expected load out. And I plan on keeping some empty 55 gallon barrels handy to fill up with tap water if things look like we might be needing it. I can't keep these 'spares' filled because I don't have a place to keep them that they don't end up having to be moved on too frequent a basis or they'll be in areas that I don't want to subject to the weight. 55 gallons of water per is just too heavy to do that with.
We do get freezing temperatures for long enough periods every now then so called/long term that at times you can go ice skating on ponds. Those are rare years, especially these days (but climate change is a myth right?) but still a concern. In a store every drop situation, I'm not sure how we'll handle it. I would assume that the barrels are pretty prone to splitting from water expansion during a heavy freeze. That would mean they'd have to at least live in a non-freezing space during those times. Of course in a bad situation I'm not sure how much of the house would stay non-freezing depending on how we're heating it.
We use air pillows in our pool to help avoid cracking/breaking from the expansion during the winter, would that help at all in a barrel?
In normal times the water will be used for vegetable gardening in our garden and container fields. The shed already has a solar set up to run the lights and a couple of small fans during the heat and stereo equipment and lights for late nights by the pool. Fairly basic, a solar array from northern that feeds into 3 deep cycle batteries with an inverter etc. I have a couple of small fountain pumps that i use for solar heating for the swimming pool (a few hundred feet of black 1" pipe in coils laid out in the sun that recirculates the pool water) that I plan on using to pump the water for gardening. It's not a high efficiency system but it does extend the usable swimming season by a month or so, a couple or three weeks on each side. I don't enjoy cold water swimming as much these days.
Where the barrels will be stored doesn't get any sun if that will help for algae development? They'll be sitting next to a shed in a 3' space between it and a 6' wall. And just south of there is a 40' dogwood that blocks the morning sun and the noon and afternoon sun is blocked by the shed itself. IT's why I can't get anything to grow in there as it stands.
Should I assume that a small amount of chlorine should be dropped in to keep chlorine up a bit to help keep it clean?