Newark Water Hardness & Quality Report (2026)

The Alameda County Water District (ACWD) supplies potable water to Newark, Fremont, and Union City in Alameda County, California, serving over 380,000 residents across 86 square miles. Primary sources include imported surface water from the Sacramento-San Joaquin Delta via the South Bay Aqueduct processed at the Moffat Treatment Plant and the State Water Project, blended with local groundwater from the Niles Cone and Newark Basins. ACWD operates three treatment facilities: the 40 mgd Newark Facility, the 20 mgd Niles Facility, and smaller wellhead plants, ensuring compliance with state and federal standards through advanced filtration and disinfection.

Water originates from the Sacramento-San Joaquin River Delta watershed, spanning the northern Central Valley, with local augmentation from the Santa Clara Valley Groundwater Basin. The Niles Cone features Holocene alluvial deposits overlying Pleistocene gravels, recharged by percolated Delta water and underflow from adjacent basins. The mineralised character stems from prolonged contact with carbonate-rich formations in the Franciscan Complex and Great Valley Sequence, yielding a hard supply prone to scale-forming ions, moderated by blending with softer imported sources.

Hard water promotes calcium carbonate scale buildup in pipes, heaters, and fixtures, significantly impacting water heaters, dishwashers, and laundry machines by reducing efficiency and lifespan. Soap lathering diminishes, leaving residues on skin and hair. Regular vinegar descaling, low-flow aerators, and magnetic descalers help mitigate effects; a water softener is recommended for households with noticeable spotting or appliance issues. ACWD maintains pH between 8.0–9.0 for corrosion control, with full compliance on lead and copper rules and no PFAS detections above notification levels; disinfection uses chloramines with multi-barrier filtration.