Enter the RO Water (product/permeate) volume and the total (feed) water volume into the calculator to determine RO Efficiency (also called RO recovery). You may use gallons (US), liters, or cubic meters; the calculator converts units automatically.

RO Efficiency (Recovery) Calculator

Enter any 2 values to calculate the missing variable. RO Efficiency here means water recovery: (RO Water ÷ Total Water) × 100.

RO Efficiency (Recovery) Formula

The following formula is used to calculate RO Efficiency (RO recovery). Note: RW and TW must be in the same volume units (any consistent unit works).

E_{ro}=\frac{RW}{TW}\times 100
  • Where Ero is the RO Efficiency / recovery (%)
  • RW is the RO water (product/permeate) volume (e.g., gallons (US), liters, m³)
  • TW is the total water (feed) volume sent to/processed by the RO system (same units as RW)

To calculate RO efficiency (recovery), divide the RO product water volume by the total feed water volume, then multiply by 100 to express the result as a percentage.

How to Calculate RO Efficiency?

The following example problem outlines how to calculate the RO Efficiency.

Example Problem #1:

  1. First, determine the RO Water (gallons). In this example, the RO Water (gallons) is given as 300.
  2. Next, determine the total water (gallons). For this problem, the total water (gallons) is given as 600.
  3. Finally, calculate the RO Efficiency using the equation above: 

Ero = (RW / TW) × 100

Inserting the values from above and solving the equation: 

Ero = (300 / 600) × 100 = 50%

FAQ

What is RO Water?

RO Water (also called permeate or product water) is the purified water stream produced by a reverse osmosis system. Reverse osmosis removes many dissolved salts and contaminants by using pressure to force water through a semipermeable membrane.

Why is RO Efficiency important?

In this calculator, “RO Efficiency” means recovery: the fraction of feed water that becomes usable RO product water. Higher recovery generally means less wastewater (concentrate/brine) per gallon of product water. However, recovery is not the same as contaminant-removal performance (often discussed as salt rejection or permeate quality, measured using TDS/conductivity).

Can RO Efficiency be improved?

Recovery can sometimes be increased by proper maintenance (clean filters/membranes), optimizing operating pressure/flows, or using system designs like staging or recirculation. Increasing recovery too far can raise scaling and fouling risk, so it should stay within membrane/system manufacturer limits and water-chemistry constraints.