Cooling Water Circulation Share
This calculator expresses reported circulating cooling-water volume as a share of that volume plus reported makeup-water volume. It can support an internal water-balance dashboard when both inputs describe the same system, unit, and period. It does not measure equipment efficiency, cycles of concentration, evaporation, blowdown, leakage, heat removal, water quality, or regulatory compliance.
Method and formula
The implemented equation is:
rate = circulating water ÷ (circulating water + makeup water) × 100%
Both inputs must be non-negative and their sum must be greater than zero. They can be in m³, tonnes under an accepted density convention, gallons, or another volume unit, but both must use the same unit. The ratio is dimensionless, so the selected unit cancels.
The value is best described as a circulation share under this page's stated definition. Similar-sounding water-reuse, recirculation, concentration-cycle, withdrawal, and consumption indicators can use different system boundaries and formulas.
Worked example
Suppose a defined cooling system reports 950 m³ of circulating flow and 50 m³ of makeup water for the same accounting period:
950 ÷ (950 + 50) × 100% = 95%
This means 95% of the two entered quantities is the circulating-flow figure. It does not mean the facility consumed only 5% of withdrawn water, saved 95% relative to a baseline, or met a legal threshold.
What the result means
Use the result to compare measurements only when the metering and accounting conventions remain consistent. A high percentage can reflect a large recirculating flow relative to makeup, but it does not by itself show whether evaporation, drift, blowdown, leakage, chemical treatment, heat-transfer performance, or total freshwater withdrawal is acceptable.
If the objective is water conservation, track absolute makeup volume and discharge alongside the ratio. A percentage can rise while total water use also rises.
Measurement and compliance limits
- Circulating and makeup quantities must cover the same system boundary and the same reporting period. Mixing an hourly circulation rate with a monthly makeup volume produces a meaningless ratio.
- Meter calibration, estimation methods, bypass flows, multiple loops, storage changes, and unmetered losses can materially affect the value.
- A zero makeup input mathematically returns 100% when circulating water is positive, but an exact zero should be investigated rather than assumed to prove a loss-free system.
- This calculator contains no industry threshold. Applicable permits, standards, reporting definitions, and water-quality requirements must be identified for the actual facility and jurisdiction.
Sources
- U.S. Environmental Protection Agency, Guidelines for Water Reuse — industrial reuse context, cooling-water recirculation, and makeup water.
- ISO 22449-2:2020, Use of reclaimed water in industrial cooling systems — scope and terminology for evaluating reclaimed-water use in industrial cooling systems.
- China National Standard Information Public Service Platform, industrial circulating cooling-water specification record — example of a jurisdiction-specific standard that must be checked separately from this ratio.
Editorial record
- Author: SoupCalc Editorial Team
- Method review: SoupCalc Industrial Water Review
- Last reviewed: August 10, 2026
- Review scope: formula, zero handling, measurement boundary, worked example, source scope, and removal of unsupported industry thresholds