Estimate the total cost over 1–15 years
Use your own numbers. Our starting values are illustrative assumptions based on the Waterdrop UK listings checked in November 2026, not a guaranteed quote. The calculator counts replacement cartridges needed before the end of the chosen period.
Enter your own fitting quote and an electricity budget if applicable. We do not invent energy consumption figures.
£0.00 / month, averaged over the full period
What this calculator excludes
- Unknown electricity usage beyond your editable allowance, and repairs, cleaning products and unexpected replacements.
- Unquoted installation costs beyond your editable one-off fitting estimate.
- Price inflation, delivery charges, water-quality variation and possible included replacement cartridges.
- Actual output/drain efficiency changing due to flushing and operation.
These exclusions are deliberate; pretending we know exact lifetime costs would be misleading. You can compare scenarios by changing the numbers, and use your local water tariff rather than our default.
What the formula does
System cost + cartridge replacements scheduled before the final month + estimated additional reject-water cost + optional fitting and electricity allowances. It treats a pure-to-drain ratio of 2:1 as 0.5 L rejected per 1 L filtered; 3:1 as about 0.333 L rejected. Replacements occur at the manufacturer's indicative frequencies and may differ in practice.
Sources & verification
Facts below are taken from the linked sources; product information may change. Last editorial check: 13 November 2026. No hands-on product testing was performed.