On Fri, 20 Apr 2012 03:46:06 -0700 (PDT), Kelvin Kersey
wrote Re underground cistern:

Hi all. I live in a drought area and my (Victorian) house has a large
underground cistern for collecting rainwater. It is empty and has not
been used for many years (I suppose since mains water was installed)
and I'm wondering whether I could use it again by diverting drainpipes
or just the overflow from water butts. Does anyone know anything about
this sort of thing? I wouldn't like to make the ground soggy and have
the house tip into it. Am I being alarmist. Any advice appreciated.
Thanks

If it's not too large, maybe you could fill it and then monitor the
water level to see if any leaks out. If no leaks, I can't think of a
reason not to use it as you suggest.
--
Work is the curse of the drinking class.