Gahanna Water Hardness & Quality Report (2026)

Gahanna, Ohio, in Franklin County — a major northeast Columbus suburban community (Gahanna is one of Franklin County's significant northeast suburban communities in the Columbus metro — a predominantly residential community along Big Walnut Creek northeast of Columbus), home of one of the largest concentrations of corporate headquarters in the Columbus northeast suburban corridor, a diverse Franklin County community with a significant Vietnamese-American population (Gahanna has one of the larger Vietnamese-American communities in central Ohio, with a significant Vietnamese commercial district along Hamilton Road), and a growing Columbus suburban community adjacent to John Glenn Columbus International Airport — draws its municipal water supply via the City of Columbus Division of Water. Water hardness in Gahanna measures 135.5 mg/L — classified as moderately hard.

Gahanna's moderate hardness — significantly softer than nearby Upper Arlington (209.5 mg/L) — reflects variation in the Columbus Division of Water distribution across the northeast Columbus zone. The Columbus water system draws from the same Scioto River and Silurian–Devonian carbonate geology (Niagaran Dolomite, Delaware Limestone). The northeast Columbus distribution to Gahanna involves newer post-1970s suburban mains, producing the moderate 135.5 mg/L compared to the inner-ring Upper Arlington zone.

At 135.5 mg/L, Gahanna residents encounter moderate scale accumulation. Monthly cleaning with citric acid solution is recommended. Columbus Division of Water consistently delivers water meeting all Ohio EPA and federal EPA Safe Drinking Water Act requirements.