On February 27, 1989, the Los Angeles Regional Water Quality Control Board (Regional Board) adopted Waste Discharge Requirements (WDR) Order No. 89-16 for the disposal of treated groundwater at the former Placerita Canyon Facility in Canyon Country, California.

Quarterly groundwater monitoring has been conducted at the site for nearly 20 years. The data from groundwater samples collected from monitoring wells indicate the extent of VOCs is localized to two specific monitoring locations at the site. The groundwater data from extraction well samples collected from the main downgradient extraction well field show that VOCs have only been detected at two extraction well locations during the past five years (or before). In addition, a single extraction well located in an upgradient area of the site does not contain sufficient groundwater to be extracted or treated.

Additional studies conducted from 2002 to 2009 for the purpose of characterizing either the extent of VOC-impact groundwater or identifying potential VOC source areas did not indicate VOC-impacted groundwater to extend beyond the two localized areas or identify the presence of VOC source areas. These additional studies included a soil gas survey, a comprehensive site-wide groundwater investigation, installation of additional monitoring wells and groundwater sampling, a "hydropunch" investigation, and soil sampling.

Currently, the concentration of only one VOC at one monitoring well location exceeds its maximum contaminant level.