Methods used for drilling, installation or development of groundwater bores, or collection of groundwater samples can be a significant source of error in groundwater quality data. This guideline has been developed to assist those undertaking bore drilling and installation, bore development and groundwater sampling to reduce the potential for error. This guideline will help subsequent groundwater management decisions to be based on ‘representative’ groundwater quality data. This guideline also outlines sampling methods to enable comparison of analytical results against relevant guidelines including the Environment Reference Standard (ERS).