Nobody decides to buy bottled water. You just keep buying it – two five-litre bottles here, a pack there – and the cost gets diluted in the supermarket bill until you no longer notice it.
This article adds it all up. Using industry data, actual tariffs, and three different consumption scenarios, so you can compare it with what you spend at home.
How much do we actually drink?
According to data from APIAM (Portuguese Association of Natural Mineral and Spring Water Industries), Portuguese people consumed approximately 1.215 billion litres of bottled water in a single year, which corresponds to a per capita consumption of 146.4 litres — a value that five years earlier was 113.6 litres.
Portugal is among the European countries with the highest per capita consumption of bottled water. And approximately 85% of this volume comes in plastic packaging.
It's worth noting the contrast: we are drinking more and more bottled water in a country where tap water meets legal quality criteria in almost 99% of official analyses.
Scenario A — national average consumption
A family of four, at the national average consumption of 146.4 L per person, buys about 585 litres of bottled water per year.
| Format | Average price per litre* | Annual cost |
|---|---|---|
| 5 L bottle | ≈ €0.13 | ≈ €76 |
| 1.5 L bottle | ≈ €0.30 | ≈ €175 |
| 0.5 L bottle | ≈ €0.60 | ≈ €350 |
*Indicative market values, for calculation purposes. They vary considerably depending on the brand, retail outlet, and promotions. Use the prices you usually pay to recalculate.
Scenario B — the family that only drinks bottled water
Many households do not use tap water for anything to drink or cook with. Considering 1.5 L per person per day — drinking water, tea, coffee, soup, rice — a family of four reaches 2,190 litres per year.
| Format | Annual cost | Over 5 years |
|---|---|---|
| 5 L bottle | ≈ €285 | ≈ €1,425 |
| 1.5 L bottle | ≈ €657 | ≈ €3,285 |
| 0.5 L bottle | ≈ €1,314 | ≈ €6,570 |
The difference between buying in 5-litre bottles and small bottles is more than €1,000 per year — for the same water.
And tap water, how much does it cost?
This is the part that usually surprises people. The same 2,190 litres correspond to 2.19 m³. With supply tariffs in Portugal typically ranging between €1.5 and €2.5 per m³ (including associated components, and varying from municipality to municipality):
2,190 litres of tap water ≈ €3 to €6 per year.
In other words: between 50 and more than 200 times cheaper per litre than bottled water, depending on the format you compare it to. Your municipality's tariff is on your water bill.
The costs no one adds up
The price of the bottle is only the visible part.
- Transport. 2,190 litres is about 438 5-litre bottles per year — more than eight per week, nearly 42 kg carried from the car to the house every week. Anyone living in a building without a lift knows this calculation well.
- Space. Large bottles take up pantry space, balcony space, or that corner of the kitchen that would be useful for something else.
- Time and trips. Trips to the supermarket mainly motivated by water, or online grocery delivery fees that are higher due to weight.
- Plastic. Considering an average weight of 19.32 g per package, it is estimated that each Portuguese person generates about 2.4 kg of plastic waste per year just from bottled water. In a family of four, almost 10 kg.
When does a purifier pay off?
Let's be precise: a purifier has an acquisition cost, filter costs, and electricity costs. The comparison is only honest if you add all three.
| Component | Estimated value |
|---|---|
| Replacement filters | ≈ €60–120 / year |
| Electricity | ≈ €15–30 / year |
| Mains water consumed | ≈ €5–10 / year (including reject water) |
| Annual usage cost | ≈ €80–160 |
With an average annual usage cost of about €110, the five-year comparison for scenario B is as follows:
| Option | Year 1 | Total over 5 years |
|---|---|---|
| 1.5 L bottles | ≈ €657 | ≈ €3,285 |
| 5 L bottles | ≈ €285 | ≈ €1,425 |
| €549 purifier + consumables | ≈ €659 | ≈ €1,099 |
| €899 purifier + consumables | ≈ €1,009 | ≈ €1,449 |
Reading these figures, without exaggeration:
- Against 1.5 L or smaller bottles — the purifier typically pays for itself in the first or second year.
- Against 5 L bottles — the return is slower, around 3 to 4 years. Here, what usually influences the decision is not money, but avoiding carrying heavy weights and having water at the right temperature at any time.
- If you drink little bottled water — it probably doesn't pay off financially, and a filter jug would better suit your needs.
Important: these values are illustrative examples, calculated with average market prices and consumption estimates. They do not constitute any guarantee of savings. Your result depends on the price you pay today, the volume you consume, and your municipality's tariff.
The environmental aspect
The energy difference is of another order of magnitude. It is estimated that producing 1 litre of bottled water requires between 5.6 and 10.2 MJ, while treating and distributing 1 litre of tap water is around 0.005 MJ. Several studies point to a carbon footprint of tap water up to 300 times lower than that of bottled water.
For a 500 ml bottle, the estimated total footprint is around 82.8 g of CO₂. This calculation multiplies quickly in a household that consumes thousands of litres per year.
Calculate your own in 30 seconds
- See how many litres of water you buy per week (large bottles × 5, or packs × 1.5).
- Multiply by 52. That's your annual consumption.
- Multiply by the price per litre you usually pay. That's your real annual cost.
- Compare with about €110 per year for a purifier's running cost, plus the initial investment spread over the years you expect to use it.
If the number in point 3 surprised you, you now know what you were paying without realising it.
Frequently asked questions
What is the cheapest way to buy bottled water?
The 5-litre bottle is clearly the format with the lowest cost per litre — it can cost less than half per litre than 1.5 L bottles and about a fifth of individual 0.5 L bottles. On the other hand, it is the heaviest and most inconvenient to transport and store.
Is tap water safe to drink in Portugal?
Yes. ERSAR's "Safe Water" indicator was 98.86% in 2024, meeting the 99% target for the tenth consecutive year. The reasons why families prefer bottled water are mainly the taste of chlorine and water hardness, not safety. We explained this in detail in this article.
How long does it take for a water purifier to pay for itself?
It depends entirely on what you spend today. Compared to 1.5 L bottles, the return usually occurs in the first or second year; compared to 5 L bottles, it's around 3 to 4 years. Those who consume little bottled water are unlikely to see a significant financial return.
Does a purifier consume a lot of water?
Reverse osmosis systems produce reject water — part of the water is used to flush away what is retained in the membrane. In countertop devices, this water is collected in a dedicated tank. Even adding this portion, the cost of mains water remains a marginal fraction of the total cost.
And the filters, how much do they cost per year?
It varies with the model, the quality of the source water, and consumption. This is the most important item to confirm before buying: always check the price and frequency of filter replacement in the product specifications, and add them to the device price before comparing options.
In summary
A Portuguese family that drinks exclusively bottled water spends, depending on the format, between €285 and over €1,300 per year. The same amount of tap water costs €3 to €6.
This difference alone is not a reason to stop buying bottled water — some prefer the taste, and it's a legitimate choice. But it is enough reason to consciously calculate the cost, instead of letting it get lost in the supermarket receipt.
If you decide to proceed, start by understanding which technology is suitable for the water in your area: water purifier buying guide.
Or directly view our range of countertop reverse osmosis purifiers — no installation, free shipping to mainland Portugal, and a 3-year warranty.
Sources: APIAM — pre-packaged water consumption data in Portugal; Água da Torneira portal — consumption and environmental footprints; ERSAR — RASARP 2025 (2024 data).
All calculations presented are illustrative examples based on average market prices and consumption estimates. They do not guarantee savings.