Desalinated water can undergo some chemical changes during storage, although these are usually minor if the reservoir is well managed. Because desalinated water has very low mineral content, it is more chemically “aggressive” than natural freshwater. To make it stable, utilities often add minerals such as calcium or magnesium and adjust pH before storage. This process, called remineralization, reduces the risk of corrosion in pipes and tanks.
During storage, the main chemical change is the decline of disinfectant levels. Chlorine or chloramine, which are added to keep the water safe, gradually dissipate, especially in warm climates or in open reservoirs. If disinfectant levels drop too low, operators may re-dose the water to maintain safety. Other changes can occur if water remains stagnant. Dissolved oxygen levels may decrease, while microbial activity, if not controlled, can alter taste and odor. In covered or well-maintained reservoirs with proper circulation, these changes are minimal and regularly monitored.
