Originally, water officials thought they would use one plant and transmission system to clean all the water in the Irvine Subbasin of the Orange County Groundwater Basin. Part of the ground water under Irvine and the former Marine Corps air base is a toxic plume contaminated by pollutants from base operations. The public was not comfortable with water from the toxic plume going into the drinking water supply, even after purification, despite the fact it would be safe to do so, according to Joyce Wegner-Gwidt of the water district.
Other water under Irvine has a high natural mineral content and is contaminated with nitrates from past agricultural practices, mainly crop fertilizing. The public will tolerate this water being cleaned and put in the drinking water supply, according to the water district.
The Irvine Desalter Project will clean up both sources of water - under Irvine and the former air base.