Desalination is a set of engineered processes that remove dissolved salts and minerals from saline water, producing water that meets drinking‑water standards. The most common technique, reverse‑osmosis, forces water through semi‑permeable membranes under high pressure, leaving salts behind. Variants such as multi‑stage flash distillation and electrodialysis are also used, each suited to specific feed‑water qualities and energy contexts.

By converting an abundant, yet non‑potable, resource—oceans and brackish aquifers—into usable fresh water, desalination directly expands available supply. In regions where drought, over‑extraction, or climate variability limit rivers and groundwater, desalinated output provides a stable, controllable source that can be ramped up to meet demand, thereby softening the impacts of water scarcity.