BCL writes:
Even outside the city there are dangers. A friend's water tank was
infested with thread worm, they presume from bird shit,

Umm, lovely. :-(

I once climbed up to clean out the gutters from a house that had a
sparrow problem. Not only had the one inch of rotting straw and manure
caused the gutter to rust through, but I found it to be crawling with
maggots! (Before this, I thought their tank water tasted real good.)

Another time, on my uncle's farm the water began to smell worse and
worse. They thought that something must have fallen down the well
over at the windmill. But one day as I was riding past the tank on
the hillside I edged the horse over to its side and looked in -- there
was a dead crow floating on the surface! So I got a stick and attempted
to fish it out but it fell to pieces and sank to the bottom. After
that we only used that tank's water for bathing! Such is life on the
land....
--
John Savage (news address invalid; keep news replies in newsgroup)