This report presents an inventory on the status, current condition and capacity of the existing Willunga Basin observation well network which has been installed to provide information needed for groundwater resource management. A review of the observation well network has found that a number of the older wells should be replaced due to their poor condition. In addition, some other observation wells will require geophysical logging, to determine their current completion condition, plus pump testing and full chemical analyses of the accessed groundwater, to be carried out. A recent review of groundwater monitoring trends throughout the Willunga Basin has also highlighted the need to expand the observation well network in areas that are showing the potential development of cones of depression. Upgrading and expansion of the existing network will be critical to the future management of the water resources in this region, especially where opportunities may arise to manage the major aquifer systems as independent units rather than as a single system. Managing the aquifer systems as independent units may allow additional water to be available for irrigation use.