Urban water in Gulf Cooperation Council countries is principally supplied from desalination plants. However, desalination could be interrupted by natural hazards such as cyclones or harmful algal blooms. Four scenarios have been considered to help public institutions in Muscat to establish a water strategy for emergency situations. The numerical simulations of groundwater pumping have shown that the aquifer can supply emergency water in a safe way without any apparent risk of seawater intrusion to the Al-Khod Aquifer. The results show that Muscat can be easily supplied by emergency groundwater for up to 10 consecutive days with volumes varying between 24 and 71 l/cap/day at a low cost of US$0.18 per m3. Covering up to 66% of the total regular demand during an emergency is technically feasible but would bring the cost up to US$1.49 per m3 for groundwater and a cost of US$38.6 per m3 for storage reservoirs made of concrete. The cost per m3 of using concrete reservoirs is close to the market price of bottled water. Finally, the Public Authority for Electricity and Water might think of decentralizing the water storage at house levels by requiring new houses to be equipped with reservoirs on the roofs.