If you are going to drill a well or have the money, drill into rock. There are oceans of water far below the aquifer. It is under pressure and comes up thru vertical rock fissures. Once tapped it doesn't stop, unless rarely an earthquake might alter water path thru the rock. It has been drilled for since the 1920's but it's hardly mentioned since water control is power and unlimited water is not wanted. Search, primary water.
Since antiquity, the source of water generated deep within the Earth, clearly defying the conventional scientific hydrologic cycle explanation, has been a mystery. How does one explain sources of water throughout the world that produce impressive quantities of fresh water, often in dry areas with little rainfall or at high altitudes? Besides numerous oases in Sahara, Arabic Peninsula, Middle East and the driest deserts elsewhere, and countless springs at mountain tops worldwide, there are clear examples of this phenomenon which stand out, like the Ain Figeh spring near Damascus, the Montezuma Well in the Sonora Desert in Arizona or the Zamzam well in Mecca."
A spring in Oregon flows at 690 million gallons a day, a spring in Missouri flows at 800 million gallons a day called Big Springs, MO., and a series of springs along the Snake River in Idaho flow at 3.5 billion gallons a day." all primary water
In the 1950's, flooding impeded construction of the Tecolote Tunnel through the Santa Ynez Mountains. By its composition and the depth at which it was encountered, the thirteen million gallons a day was not rainwater. Some of the water was hot, as much as 117 degrees Fahrenheit, and mineralized, some was cool and exceedingly pure. The flows were stopped so construction of the six-mile long tunnel to connect Santa Barbara to the Cachuma Reservoir could continue."
Stephan Riess, spent decades himself in quest of primary water, and is an early pioneer in the field, as described in the book,"New Water for a Thirsty World" by Michael Salzman. In 1958, Israel's Prime Minister David Ben-Gurion asked Stephan to find primary water to supply a new city, and port on the Red Sea, under construction. In May 29,1959, the Jerusalem Post announced that the Riess-located wells were sufficient to supply a city of more than 100,000 people, enough to supply the city of Eilat, and outlying villages. — Link
"One cubic kilometer of granite, under the right conditions, will yield one billion gallons of primary water." — Stephan Riess
"Primary water wells are not a new phenomenon. Stephan Riess was drilling wells all over California and in the Middle East as far back as the early 1930s. Pal has traveled to Africa numerous times, drilled six wells in Kenya and Tanzania, producing over 3,000 gallons per minute in an arid land with less than 10 inches of rainfall per year."
The Science of Water
NEW SCIENTIST: Planet Earth makes its own water
WATER Journal - Information about water
Earth's Deep Water Cycle - ISBN978-0-87590-433-7
USA Today - Hydrogen & Oxygen trapped inside the Earth's Mantle Rock
Are there oceans hiding inside the Earth? BBC