A groundwater well is an excavation and structure created by digging, driving, or drilling to access water located in an aquifer. Modern groundwater wells bring the water to the surface by means of an electric pump. Most well water is potable with little or no treatment. According to the California Department of Water Resources, there are nearly two million groundwater wells operating in California with approximately 7,000 to 15,000 new wells constructed each year. The depth required to reach water varies from 30 feet to more than one thousand feet. Aquifers can be found in many areas of California including the High Desert and Low Desert. The best site for a groundwater well is usually determined by a hydrogeologist or groundwater surveyor. Well Drilling Contractors (Classification C-57) are licensed to install and service groundwater wells in California.
Springs and seeps occur where groundwater discharges to the surface. Seeps are wet areas, while springs have flowing water. A seep, also known as a flush, reaches the surface from an underground aquifer. Springs with a substantial flow of water often serve as the headwaters for streams and rivers.