Abandoned or unused wells can deteriorate over time and threaten groundwater. As a well owner, you must ensure your well is compliant with legislation so that it does not pose a risk to groundwater. The Water Sustainability Act and Groundwater Protection Regulation (GWPR) state that unused wells with no plans for future use must be decommissioned. Decommissioning involves completely filling in the well. This work can only be done by or under direct supervision of a Registered Well Driller.