11 trillion gallons is close to a whole year's worth of the 43 million acre-feet of water that California as a whole uses in a single year (that's a bit over 14 trillion gallons). So if all of California stopped using all water for one year, we would be in great condition. Obviously that is not realistic.
I hope the above helps people realize how major the current California drought is. The numbers are estimates. Clearly different model toilets, dishwashers, etc. are going to have different water usages. Because 11 trillion is so huge this page only takes one second to increment a minutes worth of water for the gpm categories. Otherwise you would be here all month waiting for the water usage to make a dent in the drought number. I did try to be accurate for the water usage numbers. Some of the websites that I looked at when searching for numbers include: