Southglenn Water Hardness & Quality Report (2026)

Southglenn (Centennial/Arapahoe County), Colorado, an unincorporated community and designated place in Arapahoe County south of Denver — a major south Denver suburban community in the Centennial area (now largely incorporated into the City of Centennial, Arapahoe County), a major south Denver commercial corridor (The Shops at Southglenn mall, a major south suburban commercial hub), and a representative south Denver metropolitan suburban community — draws its municipal water supply from Denver Water or South Suburban Water Authority. Water hardness in Southglenn measures 100.5 mg/L — classified as moderately hard.

Southglenn's moderate hardness reflects the south Denver metro's mixed supply characteristics. Denver Water supplies the south metro area with water from the South Platte River and Dillon Reservoir (the Colorado Rockies Blue River and South Platte watersheds — Precambrian granite and gneiss plus Cretaceous calcareous sedimentary formations of the Colorado Front Range, treated at the Denver water treatment plants). The South Suburban Water Authority also serves portions of the area, using Denver Basin artesian aquifer water (moderately calcareous calcareous Dawson and Denver Formation aquifers). The effective Denver Water treatment produces the moderate 100.5 mg/L.

At 100.5 mg/L, Southglenn residents encounter moderate scale accumulation. Monthly cleaning with citric acid solution is recommended for faucet aerators and showerheads. Denver Water consistently delivers water meeting all Colorado CDPHE and EPA Safe Drinking Water Act requirements.