How is water used in California?

Water in California is shared across three main sectors.
According to PPIC's review of data provided by the State Water Board, average state-wide water use is roughly 50% environmental, 40% agricultural, and 10% urban, although the percentage of water use by sector varies dramatically across regions and between wet and dry years. Some of the water used by each of these sectors returns to rivers and groundwater basins and can be used again. (These official estimates were last updated in 2010, so they do not reflect recent drought-related changes in water use.)

http://www.ppic.org/main/publication_show.asp?i=1108

 SOURCE: Department of Water Resources (2013).  California Water Plan Update  (Bulletin 160-13).  NOTE: The figure shows applied water use. The statewide average for 1998-2010 was 79.8 MAF. Environment (40.5 MAF average) includes water for "wild and scenic” rivers, required Delta outflow, instream flows, and managed wetlands. Urban (8.3 MAF) includes residential, commercial, and industrial uses, and large landscapes. Agriculture (31 MAF) includes water for crop production. Net water use—i.e., the volume consumed by people or plants, embodied in manufactured goods, evaporated, or discharged to saline waters—is lower. The figure excludes water used to actively recharge groundwater basins (3% for urban and 1% for agriculture on average), conveyance losses (2% for urban and 7% for agriculture), and water used for energy production (less than 2% of urban use).

SOURCE: Department of Water Resources (2013). California Water Plan Update (Bulletin 160-13).

NOTE: The figure shows applied water use. The statewide average for 1998-2010 was 79.8 MAF. Environment (40.5 MAF average) includes water for "wild and scenic” rivers, required Delta outflow, instream flows, and managed wetlands. Urban (8.3 MAF) includes residential, commercial, and industrial uses, and large landscapes. Agriculture (31 MAF) includes water for crop production. Net water use—i.e., the volume consumed by people or plants, embodied in manufactured goods, evaporated, or discharged to saline waters—is lower. The figure excludes water used to actively recharge groundwater basins (3% for urban and 1% for agriculture on average), conveyance losses (2% for urban and 7% for agriculture), and water used for energy production (less than 2% of urban use).