Crest Hill Water Hardness & Quality Report (2026)

Crest Hill, Illinois, in Will County — a Will County city in the Joliet metropolitan corridor adjacent to Joliet and Lockport, in the Illinois-Michigan Canal Heritage Corridor along the Des Plaines River — receives its municipal water from Illinois American Water, which draws from the DuPage River or the Kankakee River system in the Will County Illinois-Des Plaines River corridor, or from the regional Lake Michigan supply through the Chicago metropolitan distribution network for northern Will County communities.

The moderately hard 104 mg/L hardness and TDS of 158.9 mg/L are relatively moderate for northeastern Illinois — significantly softer than the Mississippi-sourced Quad Cities supplies (East Moline 206.5 mg/L). This suggests Crest Hill's supply draws from Lake Michigan through the Chicago metropolitan network (Lake Michigan water is ~103 mg/L hardness at Chicago — Silurian dolomite escarpment plus Precambrian Shield input) rather than purely local DuPage-Kankakee sources (which typically run harder). The Silurian Niagara Dolomite underlies Will County bedrock but Lake Michigan's diluted supply moderates finished water hardness for the northeastern Illinois distribution zone.

At 104 mg/L, Crest Hill's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and faucet aerators need periodic cleaning. Quarterly descaling is appropriate. The PFAS level of 3.8 ppt is favorable for the Chicagoland metro — Crest Hill's Will County residential character, the Joliet-Lockport industrial corridor's modest PFAS legacy, and the Lake Michigan supply's regional dilution capacity combine to produce a modest PFAS background.