Running costs
What will a water filter cost over 1, 3 and 5 years?
Enter what you’ve found for a filter you’re considering: the price, the replacement cartridges and how often they’re changed. You’ll see the total for one, three and five years, with every cartridge change listed.
Start from:
The examples are illustrative figures to show how the calculator works. They are not real products or prices. Whatever you type stays in your browser.
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Filling it in
| Figure | Where to look |
|---|---|
| Initial price and delivery | The seller’s page for the exact model. Note the date, since prices change. |
| Installation | A plumber’s written quote, or 0 if you’ll fit it yourself. See the plumbing section of the under-sink guide. |
| Cartridge set cost | The price of the replacement code in the manual, for one full change. Check it is in stock. |
| Change interval | The manual’s maintenance schedule. If it gives months and litres, enter both under the cartridge and add your daily use under Advanced. |
| Several cartridges | Add one entry for each stage: RO systems often have pre-filters and a membrane on different schedules. |
How the totals work
- Totals run from the day the filter is fitted. A cartridge set due exactly at the end of a period counts in the next one.
- Cartridges included in the price are listed but not charged again. Each cartridge in a system has its own schedule.
- If something needed is missing, the total reads “incomplete” rather than £0.
- Totals include the purchase, delivery, installation and replacement cartridges you enter. Electricity, water use, servicing and future price changes are not included.
- The calculator does not assess what a filter removes. More on how we check.
- Not sure how often a cartridge needs changing? How change dates work. Choosing between types? Under-sink and countertop guides.