Reverse Osmosis Cost Calculator

Free, no signup. Reverse Osmosis Cost Calculator.

Is reverse osmosis worth it? RO cost calculator

Work out the true cost per gallon of an under-sink RO system (system + filters + membrane) and the payback vs bottled water. Every assumption is editable and uses cited ranges -- this is a decision tool, not a sales pitch.

Typical under-sink RO; tankless/remineralizing cost more.
Every 6-12 months by use + feed-water quality.
A 2-4 person household drinks ~2-4 gal/day.
Store bottled ~$1-1.50/gal; delivery higher.
$0.13RO cost per gallon
$141RO annual cost
$1,173Annual savings vs bottled
0.2 yrPayback vs bottled

At these numbers, RO costs less per year than buying the same gallons bottled.

  • RO rejects water to drain (brine). At a typical 3:1-to-1:1 reject ratio a few product gallons add a modest water/sewer cost -- material on a well/septic or a high-tariff utility.
  • Cost per gallon falls fast as daily gallons rise: RO wins clearly vs bottled for a household that actually drinks filtered water, and loses if you would barely use it.
  • RO removes minerals too; a remineralization stage adds filter cost. These are cited ranges, not guarantees -- enter your real prices.
Where to buy Search Amazon for: an under-sink reverse-osmosis system

As an Amazon Associate, WaterByTheBook earns from qualifying purchases. The link below is an affiliate link -- it costs you nothing extra.

Not sure which fridge filter you need? Use the free Which Filter Fits finder →