"kevin" wrote in message
oups.com...
Two more considerations that I did not see in the previous replies...

1 - Water is heavy. A 300 gallon tank, full, will weigh in the
neighborhood of 2500 pounds, concentrated in just a few square feet.
This can easily collapse a roof if it isn't supported properly.

300 gallons was what they use in Korea. I can't even carry a 5 gallon water
bottle so I've got an idea of the weights involved. Based on previous
experience, they can get by with 50 to 100 gallons if "yellow/mellow"
protocols are in place.

Those storage tanks you see in other countries are put there when
the house is built, usually, and so would have proper support
underneath. Houses are often made of concrete too in many
countries, e.g., in 3rd world contries where storing water is
common. And fall down quite a bit more often than in the US.

When the big one hits sunny California there will be plenty of "all fall
down" to go around. But I get the point. Any gravity feed system will have
to be properly braced. It makes me wonder if they wouldn't be better served
by a solar water heating system that would provide a small reservoir of
water as well.

2 - Stagnant water will not be drinkable after a few months. At least,
you won't want to drink it, because it will be full of algae, crud,
slime, etc. Periodic flushing and refilling aren't really great ideas,
because eventually it will fall out of habit, or be neglected, etc. The
best idea is to just use the water continuously. E.g., find some way to
make your system such that in regular use, all water gets flushed
through the system daily. The reservoir, in other words, should be your
normal, daily water supply, replenished as needed from city water.

Another reason to look at a solar water heating systems - they are "in line"
AFAIK. The stagnant water issues are a real concern. Even water stored in
bottles gets unpleasant awfully quickly, although I suspect it's going to be
less bio-hazardous than a huge roof tank. However, in a really bad
situation, even ucky water is better than no water at all.

When power goes out, you just cut off the city supply in some
way, and rely on the water remaining in the system at the time the
power was cut.

I'm also liking the well idea more and more. That's pretty settled upon
technology.

--
Bobby G.