Ever considered how much money you could save if you swapped from bottled to tap water? We've done some maths for you, and it's enough to buy a room full of bouncy balls. Or four electric scooters. Or... read on.

Between the petition to make tap water free in restaurants and our own articles on the matter, as well as where to find water fountains where you can top up for free, we couldn't help but wonder how much money one could save by swapping from bottle to tap water in daily consumption.

The cost of tapwater

Before we get to the numbers, it should be noted that tap water charges may differ depending on the 'commune' or municipality on which you live. For our calculations, we used the cost of tap water in Luxembourg City, based on prices listed by VDL (Ville de Luxembourg).

Assuming that a 4-person household drinks 8 litres of water a day, that's 2,920 litres per year. According to VDL, one cubic metre of water (1,000 litres) costs €2.25 plus VAT (3%), so about €2.32. There's also an annual surcharge of €38.1* per household.

So at 2,920 litres per year, that translates to €6.77, plus the €38.1 surcharge for a total of €44.87.

The cost of bottled water

Calculating the cost of bottled water is somewhat trickier, as this will vary quite heavily depending on the brand and bottle size you opt for, as well as where you do your shopping. As such, we have opted to use Numbeo's average price for a 1.5 litre bottle of water, which is €0.99.

If the above household gets their full annual drinking water consumption of 2,920 litres from bottled water, that would translate to an annual cost of €1927.2.

Savings from tap water, and what it can buy you

Even if our calculations should be taken with a grain of salt, the savings from drinking tap water amount to an astounding €1,882.33 per year.

That's not far off one month's minimum wage (€2,089.75)! To put this further into perspective, it's enough to buy you:

If you stick to tap water for 10 years, you'd save around €18,220 - not accounting for interest. That's enough to buy your favourite kid a car for the 18th, or pay for a good chunk of their university education.

*There is some variation to this surcharge, we used the standard surcharge for combined meters. In fairness, one could also argue that this needn't have been included in the calculations given that you will have to pay the surcharge regardless.