Sub-metering by area (you can't manage one meter), leak survey (pressure-zone night-flow tests), trigger nozzles and washdown discipline, condensate return (it's hot, treated water), cooling-tower cycles-of-concentration optimisation, and reuse/cascading of low-contamination streams. Most are low/no-capex — which is why audit programmes report fast paybacks.
From our guide: Industrial Water Efficiency — full context, charts and sources there.
