Water is essential for life as we know it. Water grows our food, powers turbines for electricity and serves as the lifeblood of industry. Water nurtures our landscapes and provides habitat for wildlife. It is estimated between 70 and 75 percent of the Earth’s surface is covered with water, more than 96 percent of which is too salty for most human uses.

Today, significant technological developments in monitoring, assessing and treating water ensure a drinking water supply of high quality for most people.

California’s mild climate and abundant natural resources attracted early settlers, but water was the catalyst that allowed the state to grow and prosper. Capturing the water and putting it to use requires means among other things moving it from northern California, where nearly 75 percent of the state’s rainfall occurs, to central and southern California, where 75 percent of the agricultural and urban demand exists. Water development, storage and distribution projects moved the water to where it was needed most, transforming deserts into farmland and giving life to new cities and towns. Without these projects, much of the state would be different from what we see today. These projects helped make California the nation’s leading producer of food and fiber, a major manufacturing center, the most populous state in the nation, and the eighth largest economy in the world.

Today, substantial water development projects have occurred in every region of the state, from the Bay Area to Los Angeles to the burgeoning Inland Empire. Thus, residential, commercial and municipal users are drawing more of their supply from a mixture of imported and locally developed sources.

From the earliest days of U.S. history, finding and maintaining a clean water supply for drinking and other uses has been a high priority. Today, significant technological developments in monitoring, assessing and treating water ensure a drinking water supply of high quality for most people. Because of water’s long history, life-supporting properties and future use, it needs to be protected from pollutants – whether natural or manmade. Ensuring a supply that sustains life for future generations has become part of the social contract.

Where a community’s water comes from depends largely on the foresight and planning of its founders and the historic use of local lands and water sources. Some communities, such as Sacramento, claimed water rights early in their history in order to assure themselves an adequate supply far into the future. Other communities do not have access to adequate supplies of good quality local water to meet their needs. Some of these communities import water, sometimes over great distances, from state or federal water projects or large water districts.