Ashburn Water Hardness & Quality Report (2026)

Ashburn, Illinois, a neighborhood on the south side of Chicago in Cook County — a major Chicago south side community, historically a significant Irish-American and Lithuanian-American working-class neighborhood that has transformed into a majority-Hispanic and African-American community, home of a large Mexican-American community, adjacent to Marquette Park and the Marquette Park lagoon, and a major Chicago south side residential and commercial corridor — draws its municipal water supply from Lake Michigan via the Chicago Department of Water Management (CDWM). Water hardness in Ashburn (Chicago south side) measures 270 mg/L — classified as very hard.

Ashburn's very hard supply — harder than most Chicago suburbs (Northbrook: 144 mg/L; Schaumburg: 133 mg/L) — reflects the Chicago south side distribution infrastructure's very significant mineral accumulation. While Lake Michigan source water is moderately hard (approximately 130–145 mg/L), the Chicago south side distribution system — including very old cast-iron and lead-joint water mains from the early 20th century Chicago bungalow belt buildout (1910s–1940s era south side mains) — accumulates substantial additional mineral content from the Lake Michigan source supply. Ashburn's older south side mains produce the very hard 270 mg/L, substantially harder than the Lake Michigan source.

At 270 mg/L, Ashburn residents face severe hard water challenges. Scale deposits form very rapidly on all fixtures and appliances — weekly descaling and appliance protection measures are strongly recommended. CDWM consistently delivers water meeting all Illinois EPA and federal EPA Safe Drinking Water Act requirements.