Johnstown Water Hardness & Quality Report (2026)

Johnstown, Colorado, in Weld County — a Weld County town adjacent to Milliken and Greeley on the Front Range in north Colorado — receives its water from the Johnstown Water Division, drawing from the Poudre River or Big Thompson River (Weld County) through the north Colorado distribution.

The moderately soft 76 mg/L hardness and TDS of 133.4 mg/L reflect the north Colorado Front Range supply's soft to moderately soft character — softer than the south Colorado Pueblo and Arkansas River communities (Pueblo: ~225 mg/L), reflecting the Front Range Rocky Mountain crystalline watershed's lower calcareous content. The Poudre River (Weld County) drains the Rocky Mountain Front Range — Precambrian Pikes Peak Granite (insoluble — dominant), Precambrian Banded Gneiss (insoluble), and minor Paleozoic calcareous formation influence at the Front Range transition (slightly calcareous — minor contributor). The predominantly insoluble Front Range granite produces the moderately soft north Colorado supply.

At 76 mg/L, Johnstown's water is moderately soft — light scale forms slowly in appliances, dishwashers remain efficient, and bathroom fixtures need occasional cleaning. Semi-annual descaling is appropriate. The PFAS level of 2.9 ppt is very low — the Weld County north Colorado Front Range rural corridor has limited major AFFF military PFAS sources adjacent to the Poudre-Big Thompson watershed.