The process of removing dissolved minerals, such as salt, from sea water and brackish groundwater is gaining favor as a method of augmenting urban water supplies. Estimates are that seawater and brackish water desalination will increase by 10 to 20 percent in the next decade, with existing and envisioned operations eventually generating an estimated 700 million gallons per day. About two dozen seawater desalination plants are proposed along the California coast.

Estimates are that seawater and brackish water desalination will increase by 10 to 20 percent in the next decade.

Desalination has been a cost-prohibitive exercise due to the high amount of energy needed to push water through dense, compact microfilters that remove salt molecules from the water. Improvements in membrane technology have produced filters that last longer and are more energy efficient than previous models. Desalting brackish underground water, which is considerably less costly than seawater desalination, has been used for decades to increase fresh water supplies.