Calculators, no fields you don’t need
The math behind the decision
Two tools that change the bill and the shortlist: annual ownership cost, and a filter-match quiz that stays in your browser.
Specs sourced from manufacturer listings · Certified vs claims labeled · WaterVetted does not run lab tests
Annual filter cost calculator
One family’s honest running cost.
Annual cartridges
$80/yr
Running cost
$80/yr
Cartridge cost = price × cartridges/year. Pitchers and single-stage carbon filters usually have no sediment stage — leave that option off. Based on published replacement intervals and typical retail cartridge prices; heavy water users change sooner.
What are you filtering for?
Household capacity
Rough guide: 1–2 people ≈ 30–50 gallons/day, 3–4 people ≈ 50–80 gallons/day. Compare that to a system’s rated daily output before buying — under-sizing is the most common error we see. Prefer a certified RO shortlist when health claims matter more than taste alone.