Fracking Wastewater Discharged into Dirt Sump

Last October an oil well operation (most likely fracking) in Shafter was observed to be discharging wastewater into a dirt sump. This was recorded on video. The Regional Water Board saw the video this week and decided to investigate. The question is whether this practice is common and whether it is legal and safe. The concern is that groundwater beneath these sites could become contaminated.