Since 2012 and the release of BDLISA, some River Basin Districts are engaged in the adjustment of their Water Framework Directive groundwater bodies, based on this up-to-date hydrogeological knowledge. For the next River Basin Management Plans (RBMP), WFD groundwater bodies are either adjusted for following River Basin Districts or retained from 1st RBMP for following River Basin Districts or created (Mayotte island). The delineation methodology benefits from BDLISA. It consists first in cross-referencing between initial WFD groundwater bodies and BDLISA units. Then limit origins for each groundwater bodies are differenciated and each “hydrogeological” limits are replaced by the BDLISA unit limits. Thus groundwater bodies are delineated according to the improved selected limits. Finally the new reference system consistency is checked.