Turning Groundwater Clear: National City Wells Get New Treatment System by Sweetwater Authority Oct 19, 2026 Member Submitted News NATIONAL CITY. — Sweetwater Authority is nearing completion of a major water-quality improvement project designed to remove naturally occurring iron and manganese from groundwater produced by the National City Wells before it enters the Authority’s distribution system. The National City Wells Iron and Manganese Removal System Project is expected to reduce the precipitation of iron and manganese within distribution pipelines, helping minimize occurrences of discolored water and the need for distribution-system flushing. U.S. Congressman Juan Vargas (CA-52) keynoted the event highlighting the project and the importance of investing federal dollars and resources into local water infrastructure. “Investing in reliable local water infrastructure is an investment in the future of our communities,” said Congressman Juan Vargas. “This project will help improve water quality for local residents while strengthening the ability of Sweetwater Authority to make the most of an important local groundwater resource. I’m so glad to have helped secure over $950,000 in federal funding for these water infrastructure upgrades to help deliver tangible benefits to the people of the South Bay.” “Customers deserve water that is safe, reliable and affordable,” said Ditas Yamane, Chair of the Sweetwater Authority Governing Board. “This project allows us to address naturally occurring iron and manganese at the source, before they enter our distribution system. It is a proactive investment in water quality and in our ability to continue using a valuable local groundwater supply.” The National City Wells produce groundwater that meets federal and state drinking water standards. However, the groundwater contains elevated concentrations of naturally occurring iron and manganese. While these constituents do not prevent the groundwater from meeting drinking water standards, they can accumulate within distribution pipelines and contribute to occasional discoloration. Sweetwater Authority has historically managed the issue primarily through distribution-system flushing. The new treatment system is designed to address the issue before the minerals enter the distribution system. The total project cost, including design, pilot testing, construction and construction-related expenses, is approximately $8.75 million. The Authority’s project received a $959,752 federal appropriation which was secured by Congressman Juan Vargas in the FY 2024 federal budget, helping offset capital costs. The National City Wells draw fresh groundwater from the San Diego Formation approximately 800 feet below the surface. The groundwater is naturally filtered by the earth and is disinfected and tested to ensure it is safe to drink. The new treatment system will add another layer of water-quality management by addressing naturally occurring iron and manganese before the groundwater enters the distribution system. The project supports Sweetwater Authority’s strategic goal of providing high-quality water while making targeted infrastructure investments that address water-quality issues, including taste, color and odor. The Authority previously identified the National City Wells project as an investment intended to reduce or eliminate most discoloration events associated with naturally occurring iron and manganese deposits.
