Ocean Desalination

SAWS Seawater Desalination Program

Building on our achievements as a national leader in conservation and water supply management, San Antonio Water System plans to meet the city’s water needs for the next 50 years by effectively managing our existing supplies while developing new water sources for the future. SAWS 2017 Water Management Plan includes an ocean water desalination supply project as a conceptual long-term strategy (2040 – 2070) for San Antonio.

What is Desalination?

Desalination is the process of removing dissolved salts from water. The salt content of different water sources can vary greatly, making many sources too salty for drinking, like the water in the Gulf of Mexico, which contains more than 30,000 milligrams per liter of total dissolved solids.

Similarly, water from many underground aquifers also can be too salty to drink. This type of water is called brackish groundwater. Along the Texas coast, brackish groundwater from the southern half of the Gulf Coast Aquifer contains about 1,000 to 3,000 milligrams per liter of total dissolved solids. In comparison, SAWS drinking water contains less than 1,000 milligrams per liter of total dissolved solids.

Future of Ocean Water Desalination

For research, there is a need for feasibility and design studies to fill in knowledge gaps regarding potential environmental impacts and projected performance of desalination facilities. There is also a need to test the regulatory path with a demonstration facility to ensure we fully understand the permitting process and to propose any changes to the process if needed.

Texas does not yet have a seawater desalination plant. However in May 2011, voters in Laguna Madre Water District in South Texas approved a bond proposition to build a seawater desalination plant on South Padre Island that would produce 1 million gallons per day. Construction on that facility is scheduled to begin in 2013.

Perfecting the desalination technology and permitting process are not the only obstacles faced in bringing ocean water desalination to San Antonio. Another major obstacle is the cost and logistics of transporting the water via pipeline at least 140 miles inland and uphill from the coast.