The Woningwaarderingsstelsel (housing valuation system) was modified with effect from 1 October 2015. The new change means that the WOZ value now has consequences for the maximum permitted rent price for housing with unshared amenities. As of 1 October 2015, tenants of rental properties can have a stake in the WOZ value. That is why the RBG now mentions the property’s WOZ value on assessments for tenants of rental properties.
You can find more information about how the WOZ value is determined on the WOZ page.