Gage Park Water Hardness & Quality Report (2026)

Gage Park, Illinois, a neighborhood on the south side of Chicago in Cook County — a historically significant Chicago south side neighborhood that transitioned from a predominantly Eastern European (Czech, Slovak, Lithuanian, Polish) working-class community in the mid-20th century to a predominantly Mexican-American and Mexican immigrant community today, adjacent to Marquette Park (site of the 1966 Martin Luther King Jr. open housing march through Gage Park, one of the most significant civil rights demonstrations in Chicago history), and a major Chicago south side Latino residential community — draws its municipal water supply from Lake Michigan via the CDWM. Water hardness in Gage Park measures 224.5 mg/L — classified as very hard.

Gage Park's very hard supply reflects the Chicago south side distribution infrastructure's substantial mineral accumulation from the Lake Michigan source. The CDWM Chicago south side grid — including water mains from the 1910s–1940s Chicago bungalow belt buildout era (the Gage Park area was developed as a bungalow belt neighborhood primarily from 1910–1940) — accumulates very substantial additional calcium and magnesium above the Lake Michigan source water (~130–145 mg/L). The aged Gage Park south side mains produce the very hard 224.5 mg/L.

At 224.5 mg/L, Gage Park residents face severe hard water challenges. 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.