Abstract: A method for analyzing water or other liquid, in particular rain water, comprises the steps of providing a collector comprising at least first and second volumetric cells and a mechanism for causing water to flow selectively into the cells and for causing water to flow selectively from the cells. Water is caused to flow into a first one of the cells while it is prevented from flowing into the other one of the cells. The water collected in the first cell is caused to flow to a property determining cell when the first cell has been filled to a predetermined volume, and simultaneously water is prevented from flowing into the first cell while it is now permitted to flow into the second volumetric cell. The water collected in the second cell is then permitted to flow to a property determining cell when the second cell has been filled to a predetermined volume, and simultaneously the water is prevented from flowing to the second cell while it is now permitted to flow to the first cell.