Water Footprint

ISO 14046 sets the requirements for calculating a water footprint on a life cycle assessment basis. It differs importantly from the carbon footprint: water impact depends on geography. The same cubic metre of water has a far greater impact in a catchment under water stress, so the calculation is made on a catchment basis.

The aim is to reveal the real environmental impact of water use and to manage water risk according to the place of production.

• Water-intensive textile, food, beverage, paper and chemical facilities
• Organisations operating in areas of high water stress
• Companies disclosing water performance in their sustainability report
• Brands assessing their supply chain's water impact
• Investors and financial institutions conducting water-risk analysis

• Goal and scope: the functional unit, system boundaries, geographic and temporal resolution
• Water inventory: input and output water flows, distinguishing consumption from discharge
• Collecting water-quality data
• Catchment-based water-scarcity and water-availability indicators
• Impact categories: water scarcity, eutrophication, acidification, toxicity
• Distinguishing evaporation, water embedded in the product, and water returned to the catchment
• Uncertainty and sensitivity analysis
• Critical review (if the results will be published)

• ISO 14046
• ISO 14040
• ISO 14044

• ISO 14046
• ISO 14040
• ISO 14044

1. 1Definition of Goal and ScopeThe goal of the study, the functional unit and the system boundary (cradle-to-gate, cradle-to-grave) are defined. These two definitions directly determine the result.
2. 2Identifying the Product Category RulesWhere an applicable PCR or sector rule exists it is taken as the basis; comparability is possible only when the same rules are followed.
3. 3Inventory AnalysisInput and output flows across the life cycle are collected: energy, raw materials, transport, waste and emissions. Data quality requirements are applied.
4. 4Allocation and Modelling DecisionsFor multi-output processes, the allocation method, the recycling approach and the treatment of biogenic carbon are decided with their justification.
5. 5Impact AssessmentInventory data are computed against the selected impact categories: global warming potential for the carbon footprint, catchment-based indicators for the water footprint.
6. 6Interpretation and Sensitivity AnalysisThe results are interpreted together with an uncertainty and sensitivity analysis, showing how far each assumption moves the result.
7. 7Critical Review or VerificationWhere the result is to be disclosed publicly, an independent critical review is carried out; for an EPD this step is mandatory.

In footprint studies, assurance is provided through an independent critical review. Where the result is to be made public — and especially where a comparative claim is made — ISO 14040/44 requires a critical review. For an EPD, verification follows the programme operator's rules and is mandatory.

• Details of the practitioner conducting the study and of the reviewing expert
• Goal, functional unit and system boundary
• Standard applied and, where relevant, the product category rules
• Data sources, data quality and reference year
• Allocation method and modelling assumptions
• Impact assessment results
• Uncertainty and sensitivity analysis
• Critical review statement, where one was carried out

A footprint result depends on the functional unit and system boundary defined; if those definitions change, so does the result. Two studies prepared with different system boundaries or different product category rules cannot be compared. The result is not a declaration of conformity: a low or high figure does not show that the product does or does not comply with legislation.

Greenhouse gas verification and validation activities are accredited under ISO 14065; the verification itself is performed to ISO 14064-3 and the competence of verification personnel is defined by ISO 14066. Assurance engagements, by contrast, are governed by assurance standards such as ISAE 3000 and do not fall within accredited certification. In both frameworks the impartiality rule is decisive: the party that performs the calculation cannot verify that same calculation. EUROLAB holds internationally recognised accreditation from accreditation bodies that are signatories to the ILAC and IAF mutual recognition arrangements; which verifications can be offered within accredited scope is confirmed in writing at the quotation stage.

• Product Carbon Footprint
• LCA
• EPD