Tell Atlas (northern coast): 40–80 inches (1,000–2,000 mm) annually—supports agriculture, most population.
High Plateaus & Sahara (central/south): <4 inches (100 mm); hyper-arid, years without rain. Desert dominates.
Algeria is water-scarce overall. Relies on desalination, dams, fossil aquifers. Water management is a critical national challenge.