Water bills are paid at cubic meterbut how much does it correspond to? We know that one cubic meter is equal to 1000 litres and it weighs a tonbut is it a lot or a little? How much water is this actually? We try to visualize it through milk cartons and quantify it by comparing it with the water needed to carry out some daily activities.
The liter is a unit of measurement of volume, just like the cubic meter, but we are used to using liters mainly to quantify liquids (like water or milk) and perhaps for this reason it is difficult to visualize the liter as a submultiple of the cubic meter and the cubic meter as a multiple of the liter. To be able to visualize the relationship between liters and cubic metres, as a unit of measurement of volume, we can take as a reference the 1 liter milk cartons, those in the shape of a parallelepiped which in Italy are usually used for long-life milk.
The volume of a milk carton is 1 cubic decimeter, and in fact its 3 dimensions (height, width, depth), although not homogeneous, are close to ten centimeters (we can find cartons with dimensions of approximately 9.5 cm × 6.5 cm × 16.2 cm).
Now imagine having 1000 milk cartons available (the classic ones in the shape of a vertical brick), but full of water, and arranging them in this way:
- first we place 100 of them arranged in 10 rows of 10, forming a base of 10 × 10 = 100 boxes;
- then we arrange another 9 identical layers one on top of the other to form 10 layers of 100 cartons.
Since each layer is made up of 100 cartons we have in total 1000 cartonsTherefore 1000 liters of waterwhich form a column (see figure above) with a base approximately 65×95 cm wide (practically as wide as a standard kitchen hob) approximately high 162cm which is almost equal to the current average height of a woman in Italy. We can therefore visualize 1 cubic meter of water by thinking of 1000 cardboard boxes arranged to form a column as tall as a person and as wide as a hob.
But how can we quantify a cubic meter of water compared to daily uses what do we do with it? Currently the average water consumption in Italy stands at around 215 liters per day per person 1 cubic meter (1000 litres) we consume it on average in just under 5 days. Going into more detail, if a dishwasher consumes approximately 10 liters per wash, with 1 cubic meter of water we can wash the dishes 100 times, or if we use the small flush button to flush we consume 3 liters so 1 cubic meter of water corresponds to approximately 1000 ÷ 3≃ 333 flushes. In any case, returning to the bills, given that the cost of water is expressed per cubic meter and currently stands at around 3 euros (for example in a large city like Genoa the cost is 2.94 euros per cubic meter) we can say that on average every Italian spends around 3 euros on water every 5 days and that a column of water 1.60 meters high like the one in the figure above corresponds, more or less, to 3 euros.
