At least nine injection disposal wells
As the oil industry spent record amounts on lobbying in Sacramento and made record profits, documents obtained by the Center for Biological Diversity reveal that almost 3 billion gallons of oil industry wastewater were illegally dumped into Central California aquifers that supply drinking water and irrigation water for farms.
The Center said the wastewater entered the aquifers through at least nine injection disposal wells used by the oil industry to dispose of waste contaminated with fracking (hydraulic fracturing) fluids and other pollutants. 
The documents also reveal that Central Valley Regional Water Quality Board testing found high levels of arsenic, thallium and nitrates, contaminants sometimes found in oil industry wastewater, in water-supply wells near these waste-disposal operations.
The illegal dumping took place in a state where Big Oil is the most powerful corporate lobby and the Western States Petroleum Association (WSPA) is the most powerful corporate lobbying organization, alarming facts that the majority of the public and even many environmental activists are not aware of.
An analysis of reports filed with the California Secretary of State shows that the oil industry collectively spent over $63 million lobbying California policymakers between January 1, 2009 and June 30, 2014. The Western States Petroleum Association (WSPA), led by President Catherine Reheis-Boyd, the former chair of the Marine Life Protection Act (MLPA) Initiative Blue Ribbon Task Force to create so-called "marine protected areas" in Southern California, topped the oil industry lobby spending with $26,969,861.
The enormous influence that the oil lobby exerts over legislators, agency leaders, the Governor's Office and state and federal regulatory officials is the reason why Big Oil has been able to contaminate groundwater aquifers, rivers and ocean waters in California for decades with impunity. The contamination of aquifers becomes even more alarming when one considers that California is now reeling from a record drought where people, farms, fish and wildlife are suffering from extremely low conditions in reservoirs, rivers and streams.
Hollin Kretzmann, a Center attorney, criticized state regulators for failing to do their job of protecting precious water supplies from oil industry pollution - and urged Governor Jerry Brown to take action to halt the environmentally destructive practice of fracking in California. 
"Clean water is one of California’s most crucial resources, and these documents make it clear that state regulators have utterly failed to protect our water from oil industry pollution," said Kretzmann. "Much more testing is needed to gauge the full extent of water pollution and the threat to public health. But Governor Brown should move quickly to halt fracking to ward off a surge in oil industry wastewater that California simply isn’t prepared to dispose of safely.” 

