Bathroom greywater system – a babana circle The bathrooms shower and basin water are flowing into 3 banana pits, feeding the banana, paw paw and tomato trees. Greywater is sent via a pipe to the ‘basin’ around which the bananas are planted. Because the hole is lined with either paper/cardboard or banana leaves, the water gathers and is absorbed into the sides of the basin, irrigating plants. Nutrients from grey water are also taken up by micro-organisms active in the compost pile in the middle.