answer:Southern California has 2 sources of tap water – the Colorado River and groundwater. Groundwater is taken from about 4,000 ft bgs, and is filtered through subsurface soil. River water is run through a man-made filtration process. Although, either way isn’t 100% safe. Both may contain contaminants such as MTBE, Benzene, PCE, TCE, and other carcinogens. There have been many instances of tap water in the past, but regulatory agencies, such as SRWQCB, have become stricter. All in all, bottled water goes through a more strenuous filter process while other sources still contain small amounts of contaminants (but the concentrations are so low, it would not affect you even over a lifetime). Personally, I don’t think bottled water is worth the money, but is always a safe bet. Hope this helps.