Sterling Water Hardness & Quality Report (2026)

Sterling, Virginia, in Loudoun County — a major northern Virginia Washington DC suburban community (Sterling is a significant Loudoun County unincorporated community — a northern Virginia suburb in the Dulles Technology Corridor adjacent to Ashburn and Herndon; Sterling is part of the Dulles Corridor, one of the most important technology and data center corridors in the United States; Loudoun County has become the global capital of data centers — more internet data flows through Loudoun County than any other single geography on earth (the data center corridor along Route 28 in Sterling, Ashburn, and Dulles hosts more than a third of the world's internet traffic); Sterling and Ashburn are at the heart of this unprecedented concentration of digital infrastructure), a diverse Loudoun County community with a significant Indian-American (particularly Telugu-speaking South Indian American), Korean-American, and diverse technology professional population, adjacent to Herndon and Ashburn in the Dulles Corridor — draws its municipal water supply via the Loudoun Water. Water hardness in Sterling measures 158.5 mg/L — classified as hard.

Sterling's hard supply reflects the northern Virginia Loudoun County Potomac–Goose Creek watershed's calcareous-moderate character. The Loudoun Water distributes Potomac and Goose Creek supply to the northern Virginia Sterling zone with effective treatment, producing the hard 158.5 mg/L.

At 158.5 mg/L, Sterling residents face regular hard water challenges. Monthly descaling and water softeners are recommended. Loudoun Water consistently delivers water meeting all Virginia DEQ and EPA Safe Drinking Water Act requirements.