Saying hydraulic fracturing, aka fracking, has been done for a long time is a half-truth. It is the recent technology of directional drilling, high volume chemical and acid injection and multiple wells per pad which has only been done in the past 10 years that causes the concern.
Although California is not Pennsylvania, in many ways, the Marcellus shale in Pennsylvania has been extensively fracked and informs us. Those harmed are held to nondisclosure statements when they reach settlements and property values decrease. Lobbying has resulted in oil and gas industry exemption from many federal environmental regulations .
Fracking is a heavy industrial process that requires transportation to and from, and storage and use of, large quantities of chemicals wherever the site is. California oil extraction results in co-mingled, naturally contaminated brine that must be dealt with. Fracking affects air quality, infrastructure and water. Water recycling could be done by industry, but is very expensive and would require transport and disposal of the chemicals extracted. Regulations being developed would largely rely on self-policing by an industry prone to half-truths.