Cleaning frequency for RO membranes is driven by three indicators: normalised permeate flow, normalised salt passage, and normalised differential pressure. Cleaning thresholds and recommended cleaning agents differ for scaling (acid clean) versus biofouling (alkaline + biocide clean).
How often should reverse osmosis membranes be cleaned (CIP)?
The general rule is to clean when normalised permeate flow drops by 10–15 %, or when normalised salt passage increases by 10–15 %, or when normalised differential pressure rises by 15 %. In practice, most SWRO plants clean every 3–6 months; brackish-water plants every 6–12 months depending on fouling load. Waiting beyond these thresholds causes irreversible compaction and shortens element life.