Marion Water Hardness & Quality Report (2026)

Marion, Ohio, the Marion County seat — a major north central Ohio city, the birthplace of President Warren G. Harding (the 29th US President — Harding was born in Blooming Grove near Marion and served as a Marion newspaper publisher before entering politics; the Harding Memorial in Marion is a major national monument), historically one of Ohio's major manufacturing cities (Marion was a center of steam shovel manufacturing — the Marion Steam Shovel Company made some of the largest steam shovels used in the Panama Canal excavation in the early 20th century), and a diverse Marion County community — draws its municipal water supply from the Scioto River via the City of Marion Water Division. Water hardness in Marion measures 219 mg/L — classified as very hard.

Marion's very hard supply reflects the north central Ohio Scioto River watershed's highly calcareous Paleozoic carbonate geology. The Scioto River at Marion–Marion County drains: the Devonian Columbus Limestone and Olentangy Shale (highly calcareous bioclastic limestone and calcareous shale of the north Ohio Devonian Platform); the Silurian Salina Dolomite (highly calcareous evaporite-bearing dolomite of the Michigan Basin margin); and the Wisconsin Age calcareous Scioto Lobe glacial till (calcareous limestone-rich till from the Lake Erie Basin lobe). City of Marion treatment produces the very hard 219 mg/L.

At 219 mg/L, Marion residents face severe hard water challenges. Weekly descaling and appliance protection measures are strongly recommended. City of Marion Water Division consistently delivers water meeting all Ohio EPA and federal EPA Safe Drinking Water Act requirements.