This afternoon, we got out our submersible pump and connected up with some 32mm bore plastic pipe to pump the rainwater that has collected in our house, from the last couple of days of rain showers we had.



We estimated about 4500 litres of rainwater has fallen, forming a complete “lake” across the whole Floor Slab. We had about 15mm to 20mm of rain in this period of 3 days and the area of the Floor Slab is about 260 square metres which means that for every single millimetre of rainwater falling out of the sky, we would have collected 260litres of water. Since we had about 15mm to 20mm (according to the rain gauge), this means we had collected approximately 15mm x 260 litre per mm  = 3900 litres .. to .. 20mm x 260 litre per mm = 5200 litres – wow!

We spent about 2 hours pumping the water out, mostly from the 2nd sump point near the Great Room where the “lake” seems to be deeper and more connected to the rest of the Floor Slab. Initially, we had 3 lengths of output pipe connected together so we could reach the downpipe directly connected to the underground rain soakaway module and we measured the time it took to fill a 3 gallon builder’s bucket (which came out at 20 seconds). This is about 40 litres per minute. Then, when we moved up to the 2nd sump point, we had to drain the output water from the pump straight into the swimming lane itself and this meant that we didn’t need the middle section of pipe (which is a corrugated air tube) and so we connected the 32mm smooth bore pipe directly to the short fat pipe off the pump and .. o boy .. it took only 15 seconds to fill our bucket up! This translated to an increased rate of 55 litres per minute!

By Shaun

Leave a Reply