On Sun, 13 Apr 2003 18:56:53 +0100, Mike wrote:

This will give an annual volume on the clubhouse roof of approx 750 cubic
metres! The tank will need to be 10 by 10 by 7.5 metres! It might be
better to calculate the volume of water needed during a drought of X days
duration for its tank might be smaller but still meet requirements.

This is why I would like the figure per month because at no time will
the total annual rainfall be in the tank at the same time :-))

You'd still need to allow for 3 - 6 months capcity though - because you
are unlikely to be watering between (say) Nov - Feb. - assuming you can
get enough capacity to store that much water withgout problems.

Have you thought about "grey" water recycling (output of sinks, showers
etc., goes to flush the toilets and wash the car, water the garden) as
well? That could significantly reduce the amount you put down the drains.
The rainwater could also be used for showers, but it would need to be
trated to be 'potable' if you wanted to use it for drinking etc.

Sarah