Global Reporting Initiative+Third-party water withdrawals, GRI 303-3-a (formerly G4-EN8-a)+Woolworths Holdings Limited+2016+Discussion
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water source is not defined as significantly affected by withdrawal. All other withdrawals are from municipal sources.
The GBJ report states that 15.4m litres of municipal water were saved through the Woolworths head office water treatment plant, but not how much was used.