On Sun, 23 Apr 2017 16:13:43 +0100, The Natural Philosopher
wrote:



A lot of the water supply is gravity. Sewage tends to need pumping,
if only to get it from the buried pipes to the surface treatment
works.

People who still have a loft tank may become popular with those who
have modernised and rely on direct mains pressure.

for about 40 minutes till the tank runs dry

G.Harman

Well you wouldn't want to be too popular that is true.
It should give a bit of reserve if kept for ones own use and isn't
wasted by flushing the bog .
As you hinted it would be city and town dwellers especially those in
flats who are really dependent on mains water not failing.
Those in rural areas or with gardens may be better off if they have
thought about it, Water butts can be a source of water for flushing
the bog or you could just dig a hole in the garden if pushed.
We have about 2500 litres of rainwater stored here , and after that
there is the wildlife pond with about 6000 litres.
it can't be that poisonous if newts are living in it so a boil on a
fire should make it acceptable compared to dying of thirst.

G.Harman