California State Water Resources Control Board Finalizes Rules for Desalination Plants

As the drought continues across California, the State Water Resources Control Board (“SWRCB”) has adopted its first-ever requirements for desalination plants in the state. Desalination – a process of removing minerals from ocean water to produce fresh water for municipal uses – has not been widely used in California because it is expensive, energy-intensive, and the state traditionally has had access to great water resources such as the Colorado River and the Sierra Nevada snowpack.  But with recent improvements in desalination technology and rapidly declining water resources, coastal communities are looking at desalination plants as way to improve the stability and reliability of their future water supply.

On May 6, 2015, after five years of development, the SWRCB adopted an amendment to its Water Quality Control Plan for Ocean Waters focused specifically on desalination plants.  The amendments require the use of certain technology standards with respect to the intake of ocean water and the discharge of the leftover brine.  The rules require all new or expanded seawater desalination plants to use “the best available site, design, technology, and mitigation measures feasible to minimize intake and mortality of all forms of marine life.”

The new rules recommend, where feasible, the use of subsurface intake technology, which rely on pipes that are buried in the sea floor.  While surface-level intake pipes could potentially have a detrimental impact on marine life, subsurface intake appears to reduce this potential impact to near zero levels.  The SWRCB’s new rules allow the regional water boards to determine during the permitting process whether subsurface intake technology is feasible at a particular plant location.  Existing plants and plants that are already permitted, such as the massive desalination plant under construction in Carlsbad, California, are exempt from the subsurface intake requirements.

If the drought continues and the energy efficiency of desalination technology continues to improve, many Californian coastal communities could soon be getting much of their freshwater from the ocean.  Hopefully the SWRCB’s new rules help provide regulatory clarity to foster the development of such projects.