Mason Water Hardness & Quality Report (2026)

Mason, Ohio, in Warren County — a major northeast Cincinnati suburban community (Mason is one of the most affluent and rapidly growing northeast Cincinnati suburbs in Warren County — home of Kings Island amusement park, one of the premier regional amusement parks in the Midwest and one of the largest in the United States, a major employer and tourist destination), a diverse Warren County community with a significant Chinese-American, Indian-American, and professional suburban population (Mason is a major destination for Asian-American professional families in the Cincinnati metro — its school district is one of the top-rated in Ohio), home of an extraordinary concentration of sports entertainment facilities (Mason is home of the Lindner Family Tennis Center, host of the Western and Southern Open ATP Masters tournament — one of the most significant tennis events in the United States), and a major northeast Cincinnati technology and healthcare corridor — draws its municipal water supply via the Greater Cincinnati Water Works. Water hardness in Mason measures 113 mg/L — classified as moderately hard.

Mason's moderate hardness reflects the effective GCWW softening of the naturally very hard southwest Ohio Ordovician limestone supply. The Greater Cincinnati Water Works (Ohio River–Little Miami River watershed — draining the Ordovician Kope and Eden Formations, highly calcareous) applies effective lime softening, distributing to the Mason–Warren County northeast zone, producing the moderate 113 mg/L.

At 113 mg/L, Mason residents encounter moderate scale accumulation. Monthly cleaning is recommended. GCWW consistently delivers water meeting all Ohio EPA and EPA Safe Drinking Water Act requirements.