If the company is reporting on water usage of their external contratcors in the supply chain, the value should be Yes
If the company is not reporting on water usage of their external contractors in the supply chain, the value should be No
If the researcher is not 100% confident whether the information found about the company reporting on water usage in the supply chain is sufficient to state yes, the value should be Unknown
Ideally values of Unknown should be backed up wit a rationale, where possible.
First point of action should be to look at the corporate website and to look for the sustainability report. If they report on external water usage of contractors in the supply chain, then the value should be yes, if no information can be found then the value should be no.
When no sustainability report can be found then look for specific sections on the corporate website, whether they are mentioning a water management supervision system and whether they report on water usage of external partners in the supply chain.
Please also consider to contact the company directly when necessary.