This study investigates the feasibility of earthquake forecasting in northern Iceland using changes in groundwater chemistry. Building on a 2014 study showing groundwater chemistry changes preceding two M≥5 earthquakes, this research analyzes data from 2014-2023. The results indicate that one of the three M≥5 earthquakes during this period could have been forecast based on statistically significant changes in groundwater chemistry 4-6 months prior. Oscillatory changes in chemistry suggest crustal dilation and fracture mineralization associated with pre-earthquake stress buildup. The study proposes a method for implementing this approach elsewhere, emphasizing the need for long-term monitoring of groundwater chemistry.