RO recovery is the percentage of feed water that becomes permeate. Higher recovery saves water but increases scaling and fouling risk. The table below gives typical design recoveries.
| Feed water type | TDS range (mg/L) | Typical recovery | Key concern |
|---|---|---|---|
| Soft rainwater / low TDS | < 200 | 70 – 80% | Low scaling, high recovery possible |
| Borehole / municipal (moderate TDS) | 200 – 800 | 60 – 75% | Calcium, silica scaling |
| Brackish water | 800 – 3,000 | 50 – 65% | Scaling, antiscalant usually required |
| High-silica groundwater | 200 – 1,500 | 50 – 60% | Silica scaling limits recovery |
| Seawater (SWRO) | 30,000 – 45,000 | 35 – 50% | High pressure, corrosion, energy |
Design tip: Always run a scaling index calculation (e.g., Langelier Saturation Index, Stiff & Davis) before finalising recovery.