A sign on a farm trailer reading "Food grows where water flows," hangs over dry, cracked mud at the edge of a farm April 16, 2009 near Buttonwillow, California. (Photo by David McNew/Getty Images)

PALO ALTO (KCBS) — Stanford researchers have released a surprising new study revealing that California is sitting on top of a vast water resource that we didn’t know was there, and it could hold as much as 700 trillion gallons.

But, water experts say the problem with all that water may be getting to it.

“A lot of this new groundwater that researchers have found is pretty deep, and some of it’s salty, and it may be pretty hard to get to,” water expert, and President of the Pacific Institute Peter Gleick told KCBS.

Desalination of the resource would likely be cheaper than cleaning up ocean water, but aside from being deep down, the water is also far from urban areas.

MORE: Read the Stanford Study

The search for other resources below the surface could make the water unusable, according to Gleick.

“Some of these groundwater resources may be at risk from oil and gas operations, from reinjection of the wastewater,” Gleick said.

Farmers for the most part won’t have the funds to pump that water up to the surface.

“The real question that this study doesn’t answer is how much ultimately might actually be usable,” Gleick said.