It is important to have a water filtration system in your home because you need to be careful of minerals and chemicals that could be found in the different water sources (according to www.sdcwa.org ):
Colorado River
More than 50 percent of the region’s water comes from the Colorado River. The Water Authority purchases some Colorado River supplies from the Metropolitan Water District of Southern California (MWD). The Water Authority also obtains its own Colorado River water supplies through a long-term water conservation and transfer agreement with the Imperial Irrigation District and two canal-lining agreements that transfer conserved water to San Diego County. These supplies are transported to San Diego County through MWD’s water distribution facilities.
Bay-Delta
Typically in recent years about 30 percent of the region’s water has come from the Bay-Delta in Northern California. The Bay-Delta is a vast network of channels and islands at the convergence of the Sacramento and San Joaquin rivers, which collect runoff from the Sierra Nevada. The State Water Project, operated by California’s Department of Water Resources, collects water from the Bay-Delta and pumps it south to customers including MWD. The Water Authority then purchases some of this supply from MWD.
Local Supplies
Local supplies, including surface water, groundwater, recycled water and conservation, currently meet about 20 percent of the region’s water demand.”
And coming in the future water from the ocean in Carlsbad.
