My scientifically calibrated rain gauge tells me there has been a lot of rain during the night! At least the width of four strips of planking! No wonder all the watertanks are full to overflowing. How do you figure out how much rain it takes to fill a 22,500-litre tank? Easy! Go to your nearest hardware store, buy yourself a long ladder, lean it against your house, climb onto the roof and measure its * area. Then apply the following formula: 1 mm of rain collected over an area of 1 m² gives you 1 litre of water! If you have a very tiny house with just 1 m² of roof area, you'd be hoping for 22,500 mm of rain. Conversely, if you live in a huge house with a 22,500 m² roof, just 1 mm of rain will do the same. As will do any number of permutations between the two. With all those figures spinning in your head, just make sure you don't fall off the ladder as you make your way back down again.
* some of you may want to measure it's area but I won't be drawn on this; after all, it's Christmas time, the time of grammatical peace and goodwill.
