According to the Department of Water Resources, the average annual statewide precipitation over California’s land surface is about 23 inches, or 200 million acre-feet. About 65 percent of this precipitation is consumed through evaporation and transpiration by trees and other vegetation. The remaining 35 percent comprises California’s average annual runoff of about 71 million acre-feet.
Not all of this water can be used for urban and agricultural use; the environment requires a large portion to sustain healthy ecosystems. The Department of Water Resources has calculated California’s water use using a 1995 level of development:
Environmental use: 46 percent
Agricultural use: 43 percent
Urban use: 11 percent
Urban Water Use
Water plays a vital role in each segment of urban areas, whether it’s residential, commercial, industrial or municipal. Residential segments use water for drinking, cooking, cleaning and landscaping. Commercial segments use water to maintain facilities and vehicles. For industrial segments, water is required to facilitate many of the modern processes that are used.
In October 2003, AB 514 (Kehoe) was passed by the legislature and signed into law by Governor Davis. This bill requires installation of water meters and usage-based water pricing within ten years for all cities that receive Central Valley Project water, namely Fresno and Folsom.
Data show that usage-based water pricing encourages a more efficient use of water. Click here to see a chart on 2002 water consumption by the 10 largest California cities and select Central Valley communities.
Food for Thought
It’s no secret that water is used in the farming industry to help produce the food that we eat. But how much water goes into the production of the meals we eat? Let’s take a look at a simple daily menu.
One eight-ounce glass of orange juice, one egg, one piece of toast with butter and a quarter piece of cantaloupe equal 208.1 gallons of water.
One barbeque chicken sandwich, one orange and a 12-ounce glass of water equal 215.1 gallons of water.
Lasagna, one slice of garlic bread, salad and an 8-ounce glass of milk equal 470.9 gallons of water.
These add up to a daily total of 894.1 gallons of water!