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Geosptec consultants monitoring wells (MW-1 through MW-4) were installed, each to a total depth of 40 ft bgs, with screened intervals extending from 20 to 40 ft bgs. Site investigation results described in the Confirmation Monitoring Report, included no reported detections of VOCs in the 60 soil samples analyzed.PCE was either not detected or was reported at low concentrations ranging from 1.9 to 7.2 micrograms per liter(µg/L),near the maximum contaminant level(MCL)of 5 µg/L in the four groundwater samples. PCE was reported in 18 soil vapor samples analyzed, ranging from 140 to 5,600 micrograms per cubic meter (µg/m3) (Figure 3). Generally, the highest concentrations of PCE were reported in samples collected below the current Parkwoods Cleaners suite and the associated sewer lateral, and impacts appear to attenuate along the lateral with distance from the suite. Trichloroethylene (TCE)was also reported in one sample at a concentration of 91 µg/m3.The Confirmation Monitoring Report again included recommendations for Site closure though,the CVRWQCB denied the request and asked for an additional investigation work plan to delineate the vertical and lateral extent of PCE impacts in groundwater(CVRWQCB,2018b). In accordance with aAdditional Groundwater Investigation Work Plan submitted to the CVRWQCB on 22 October 2018,and a Revised Additional Groundwater Investigation Work Plan submitted on 26 November 2019, six new groundwater monitoring wells (MW-5A through MW-5C and MW-6A through MW-6c) were installed in September 2020 (E2C, 2018c; E2C, 2019; E2C, 2020). VOCs were not reported in soil samples collected from the monitoring well installation borings. Groundwater split samples were collected by the CVRWQCB in December 2020; PCE detections reported in the 6 samples collected ranged from 0.72 µg/L at MW-6C to 7.7 µg/L at MW-5C, consistent with the primary sample results. Routine groundwater monitoring at the Site has been conducted since 2019 in accordance with MRP Order No. R5-2019-0806. Analytical data from these monitoring events indicates that the Site is likely only a minor source of PCE in the area,as PCE is only intermittently reported in groundwater at low or near MCL concentrations. In contrast, domestic supply well VOC data collected as part of the MRP since 2017 has shown reported concentrations of PCE,TCE,and cis-1,2-dichloroethylene(cis-1,2-DCE)at concentrations higher than reported on the Site. PCE has been reported at the domestic supply wells ranging in concentration from 0.21 to 270 µg/L. DW-1 and DW-2 have historically had the higher reported concentrations of PCE. PCE has not been reported in samples collected from DW-3 with the exception of the last monitoring event in September 2024 where it was reported at a trace concentration of 0.21 µg/L. The most recent groundwater PCE data from Site monitoring wells and domestic supply wells is presented on Figure 4, and the historical VOC data is included in Appendix A. Based on the data collected to date, it does not appear there has been a significant release to soil or groundwater from the former dry-cleaning operations at the Site. Groundwater data, along with historical soil and soil vapor data, show that the existing on-Site groundwater impacts are not high enough PCE concentration or mass to have caused the higher PCE concentrations reported in the domestic supply wells north of the Site. Groundwater concentration data from the deep on-Site monitoring wells indicate that the impacts from chlorinated solvents to the deeper zones are very low,and that the domestic well impacts may have come from off-Site sources(E2C,2025). 4 September 2025