ABSTRACT: The purpose of this study was to identify the concentration of multi-elements (MEs) in source water (surface and drinking water) and assess their quality for sustainability. A total of 161 water samples including 88 tap drinking waters (DW) and 73 surface waters (SW) were collected from five cities in Xi'an, Yan'an, Xining, Lanzhou, and Urumqi in northwestern China. Eighteen parameters including pH, electrical conductivity (EC), total organic carbon (TOC) total nitrogen (TN), chemical compositions of anions (F-, Cl-, NO₃-,HCO₃-, SO₄2-), cations (NH₄⁺, K⁺, Na⁺, Ca2+,Mg2+), and metals (lead (Pb), chromium (Cr), cadmium (Cd), copper (Cu)) were analyzed in the first time at the five cities . The results showed that pH values and concentrations of Cl-, SO₄2-, Na⁺, K⁺, Ca2+, Mg2+ and Cd, Cr, Cu
