The true cost of drinking water
Tap water in the UK costs roughly £0.003 per litre. It is virtually free. Yet millions of households spend between £25 and £50 per month on bottled water — £300 to £600 a year. On top of that, there is the cost of transport, storage and recycling plastic waste.
The real question is not “should I filter?” but “what is the most economical way to drink quality water?”.
The economics: the tap filter
Using the Puramane filter as an example:
- Filter price: €44.90 (one-off, first cartridge included)
- Replacement cartridges: €24.90 per pack of 2, i.e. €12.45 per cartridge
- Cartridge lifespan: 2,000 litres, i.e. 3 to 4 months for a family
- Cost per litre: €0.02 (cartridge only, excluding initial purchase)
Over 1 year: filter (€44.90) + 3 cartridge packs (3 x €24.90 = €74.70) = roughly €120 in the first year, then €75 per year. Versus €400+ on bottles.
Annual cost comparison
| Solution | Annual cost (family of 4) | Cost per litre | Plastic waste |
|---|---|---|---|
| Branded bottled water | €500 – 720 | €0.20 – 0.40 | ~730 bottles/yr |
| Budget bottled water | €350 – 450 | €0.10 – 0.15 | ~730 bottles/yr |
| Filter jug | €80 – 120 | ~€0.07 | 6 – 12 cartridges |
| Standard tap filter | ~€210 | ~€0.05 | ~12 cartridges |
| Puramane filter | ~€120 (yr 1) then ~€75 | €0.02 | 3 – 4 cartridges |
Why “cheap” does not mean “low quality”
Very cheap filters from online marketplaces may have hidden costs:
- Cartridges need replacing more often (reduced capacity, often 300 to 600 litres)
- No reliable warranty or customer service in Europe
- Uncertain filtration quality (no transparent data)
- Questionable materials in contact with drinking water
Puramane, a French brand based in Fontenay-aux-Roses (92260), offers a 2-year warranty, European customer service and cartridges with 2,000-litre capacity. The truly cheap option is the one that costs least over time.
The most economical filter to run
€0.02 per litre, 2,000 L per cartridge. Filter from €44.90, cartridges x2 at €24.90.
View prices →Frequently asked questions
Which tap water filter is cheapest in the long run?
In the long run, the tap filter is the cheapest option. With the Puramane, the cost is 0.02 euros per litre, roughly 9 euros per month for a family. That is 3 to 5 times cheaper than bottled water.
How much does bottled water cost a family per year?
A family of four drinking 2 litres per person per day spends between 350 and 600 euros per year on bottled water. With a Puramane filter, that budget drops to around 100 euros per year (filter plus cartridges).
Does the Puramane filter pay for itself quickly?
The Puramane filter (44.90 euros) pays for itself in 1 to 2 months compared with bottled water. From the third month onwards, you save every day.