Groundwater Quality Groundwater is typically high-quality within the Orange County basin. The OCWD, the Orange County Basin manager, performs extensive monitoring and testing of the groundwater quality to ensure the water is safe and complies with state and federal regulations. Recharge basins and the river improve groundwater quality through natural percolation. The purified recycled water from the GWRS also recharges the Basin and because of its near-distilled water quality it improves the overall quality of the water in the groundwater basin. OCWD is proactive in studying and addressing any water quality issues within the Basin. OCWD has implemented a per- and polyfluoroalkyl substances (PFAS) treatment policy that enables constructing treatment facilities for impacted water agencies, including funding 100% of design and construction costs. OCWD constructed for IRWD a PFAS treatment facility at IRWD’s OPA Well-1 that produces water used in the Orange Park Acres area and parts of north Irvine. OCWD also provides a partial or total exemption of the Basin Equity Assessment (BEA), the charge for producing water over the BPP, for projects that improve groundwater quality. This exemption helps to compensate a producer’s treatment costs to remove poor ‐ quality groundwater. IRWD currently has BEA exemptions for pumping for Wells 21/22 and the Irvine Desalter Project (IDP) wells, as described below. IRWD has been able to successfully treat impaired groundwater to enhance the District’s local water supplies. IRWD has constructed three potable water treatment plants that treat impaired groundwater within its service area (see also Section 6). The Deep Aquifer Treatment System (DATS) was designed to remove tint from water pumped from the deepest zones of the Orange County Basin and produces 7,200 AF per year of potable supply. As described in Section 6, the Irvine Sub ‐ basin is generally high in total dissolved solids (TDS), color, and/or nitrates, and a portion of the Sub ‐ basin is contaminated with trichloroethylene (TCE) and other trace volatile organic compounds (VOCs). IRWD constructed the IDP and Wells 21/22 Desalter Project to remove the TDS, color and nitrates from otherwise non-potable water to maximize the use of local supplies. The wells overlying the Sub-basin with TCE are also treated to remove the VOC’s and then the water can be discharged into IRWD’s non-potable distribution system where it is blended with recycled water for non-potable uses such as irrigation. Other Water Quality Considerations As stated, IRWD’s drinking water is safe and meets or exceeds all quality standards set by both the state and federal government. There are continuously new and proposed changes in state and federal drinking water standards which require new monitoring and potentially new standards that must be met for various constituents. One constituent of emerging concern (CEC) is PFAS, which is a group of thousands of manmade chemicals that includes perfluorooctanoic acid (PFOA) and perfluoro octane sulfonate (PFOS). PFAS compounds were once commonly used in many products including, among many others, stain- and water-repellent fabrics, nonstick products (e.g., Teflon), polishes, waxes, paints, cleaning products, and fire-fighting foams. Beginning in the summer of 2019, the California State Division of Drinking Water (DDW) began requiring testing for PFAS compounds in some groundwater production wells in the OCWD area. IRWD’s Well OPA-1, located near the
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IRWD – 2025 Urban Water Management Plan
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