The book explains various factors that contribute to saltwater intrusion, including overuse of freshwater resources, climate change, and natural causes such as storm surges and tidal fluctuations. The impact of saltwater intrusion on coastal agriculture, including reduced soil quality, damage to crops, and alteration of ecosystems, is also explored. The study also suggests potential solutions to mitigate the impact of saltwater intrusion, including effective water management, barrier techniques, soil and crop management, and land use planning. This paper aims to investigate the problem of saltwater intrusion in the Coastal parts of Lagos and identifies that the salinization of wells is mainly due to saltwater intrusion. The research identifies four wells (AA', CMS', OBA' and VIL') as having high electric conductivities, indicating saline water intrusion, while other wells (EBM', IKJ, IKO') have lower values of electric conductivities, indicating no salt-water intrusion, and one well (AJ') shows slight intrusion from gypsum.