Stored desalinated water can become corrosive if it is not properly conditioned before entering the reservoir. Freshly desalinated water has very low mineral content and a slightly unstable chemical balance, which makes it more likely to dissolve metals and concrete surfaces it comes into contact with. To prevent this, desalination plants usually carry out remineralization, a process where minerals such as calcium and magnesium are added back into the water and the pH is adjusted. This stabilizes the water and reduces its tendency to corrode pipes, tanks, or linings.
Even after remineralization, storage conditions matter. If disinfectant levels fall too low or water remains stagnant, microbial activity and changes in oxygen balance can make the water more aggressive. In open reservoirs, evaporation and temperature changes can also influence stability.
