Calculate Water Consumption Under ASC Feed Standard

Responsible water use under ASC Feed Standard

The Aquaculture Stewardship Council established mandatory operational water use rules under Criterion 1.18 in version 1.2 of the ASC Feed Standard. This affects quality managers, compliance leads and environmental management personnel at certified feed manufacturing facilities. Feed manufacturers must calculate annual water consumption, monitor groundwater wells, assess regional water stress and implement a formal conservation plan. Conformity Assessment Body auditors inspect these water records and conservation plans during initial and annual surveillance audits.

Responsible water management ensures that feed mills consume water efficiently to maintain critical ecosystem services at the water source. Water consumption accounting captures water abstracted that was not used in feed production due to leaks or insufficiently maintained piping. The scope of Criterion 1.18 applies to all manufacturing activities from ingredient receiving through processing to final product dispatch. Failing to record consumption across all water sources or failing to express results in megalitres per tonne indicates a dysfunctional quality management system.

Auditors examine flow meter readings, pump capacity logs and utility payment invoices to verify data quality and consistency between departments. Where feed mills draw water from municipal networks, rivers, private wells or seawater, consumption must be clearly defined by source. Environmental and quality teams must cross-check water data to confirm that reported totals align with legally authorized extraction volumes under Criterion 1.1 and Criterion 1.17. Demonstrating responsible water stewardship supports operational efficiency and reduces environmental impacts in surrounding watersheds.

Step-by-step water calculation methodology

Feed mills must calculate water consumption for production following the seven-step methodology in Appendix 2, Section A1:

• Assessment period: Identify the assessment year, which is set as the previous calendar year running from 1 January to 31 December.
• Production volume: Calculate the total production volume of product in tonnes produced on site within the defined assessment year.
• Water source categorization: List all water sources used from receiving to dispatch, separated into freshwater with total dissolved solids up to one thousand milligrams per litre and other water exceeding one thousand milligrams per litre.
• Water use quantification: Calculate the quantity of water used in megalitres per water source during the assessment year, calculating consumption as water withdrawal minus water discharge.
• Total water summation: Sum the quantities of water used across all municipal, surface, ground, seawater and produced water sources.
• Water intensity calculation: Calculate total water use per total product produced per year and express the final figure in megalitres per tonne.
• Annual ASC reporting: Report the quantities used per source, total water use and calculated megalitres per tonne to the Aquaculture Stewardship Council per site according to official data submission procedures.

Well monitoring and regional water stress rules

Indicator 1.18.3 mandates that feed mills utilizing groundwater wells must measure and record groundwater levels on a regular basis. Monitoring must take seasonal fluctuations into account and occur at least once a year. Where local regulations prohibit feed mills from conducting direct well monitoring, management must obtain regulatory records to demonstrate that groundwater levels show no decreasing trend. Where flow gauges are unavailable, mills may calculate consumption using theoretical pump capacity and operating hours.

Under Indicator 1.18.5, feed manufacturers must report annually to the Aquaculture Stewardship Council whether the facility operates in a region of high or extremely high water stress. Regional water stress classification must be determined using the Aqueduct Water Risk Atlas published by the World Resources Institute. Identifying the water stress level helps feed mills determine whether changing water sources is necessary to protect local communities and ecosystems.

Indicator 1.18.6 requires facilities located in areas of high or extremely high water stress to perform an annual risk assessment. The risk assessment evaluates whether the site management plan includes adequate measures to minimize the risk of contributing to water supply problems. Under footnote 52, this risk assessment is embedded within the Appendix 7 framework, where the predefined risk factor is contributing to water supply problems for ecosystems and communities using the same water source.

Implementing a Water Conservation and Efficiency Plan

Indicator 1.18.4 requires feed manufacturers to develop and implement a documented Water Conservation and Efficiency Plan. The plan must identify responsible practices and establish measures and meaningful timelines to move away from inefficient practices, even when using municipal tap water. Under footnote 50, the plan must be embedded within the Risk Management Framework set out in Appendix 7. The predefined intent in step 1 is reducing water consumption as a result of inefficient practices, while the predefined risk factor in step 2 is not achieving the intent within a six-year period.

Responsible practices under the plan include actively detecting and repairing pipe leaks, measuring facility water footprints and improving equipment technology. Facilities can also reduce evaporation, adopt less water-demanding processes, harvest rainwater, recycle wastewater and reuse water for garden irrigation. Changing water sources from sinking private wells to municipal mains supply represents an adequate measure in high water stress zones. Bad practices include neglecting system maintenance, using water-intensive technologies and relying on non-renewable water sources.

During third-party audits, auditors evaluate top management involvement in setting water conservation objectives and targets. Auditors verify the calibration and accuracy of flow meters or compare municipal invoices against reported consumption data. Auditors also confirm that the ratio of megalitres to total production tonnage is calculated correctly without distorting consumption figures. Demonstrating active implementation of the Water Conservation and Efficiency Plan ensures ongoing compliance across the facility.

What to do now

• Map site water connections: Identify every municipal, well, surface, seawater and produced water source across ingredient receiving, processing and dispatch zones.
• Reconcile annual water consumption: Calculate total water consumption in megalitres per source for the previous calendar year following Appendix 2, Section A1 methodology.
• Verify well monitoring logs: Check that monthly or annual groundwater level measurements are documented for all site wells to confirm no decreasing trend.
• Check water stress status: Evaluate facility locations against the Aqueduct Water Risk Atlas and formalise the Water Conservation and Efficiency Plan within the Appendix 7 framework.

Reference documents

• ASC Feed Standard, V1.2, Criterion 1.18, Indicators 1.18.1, 1.18.2, 1.18.3, 1.18.4, 1.18.5, 1.18.6, Appendix 2, Section A1, Appendix 7
• ASC Feed Standard Interpretation Manual, V1.2, Criterion 1.18