World Toilet Day 2022 underlined the impact of sanitation on groundwater. In this online seminar, Dr. Konstantina Velkushanova, Senior Lecturer in Non-Sewered Sanitation at IHE Delft and Dr. Jan Willem Foppen, Associate Professor of Hydrology at IHE Delft, will share their insights and perspectives about the important, yet often invisible, linkages between sanitation and groundwater quality. The presentations will highlight mechanisms of groundwater contamination from sanitation sources, and the associated risks on water supply and public health. Furthermore, two case studies will be presented on urban aquifers affected by waste water infiltration. The discussion will explore management strategies and solutions from both domains.