Port Huron Water Hardness & Quality Report (2026)

Port Huron, Michigan, the St. Clair County seat — a major east Michigan Blue Water Area city (Port Huron is the St. Clair County seat and the principal city of the Blue Water Area — the east Michigan region at the southern tip of Lake Huron where it narrows into the St. Clair River connecting to Lake St. Clair and ultimately Lake Erie; Port Huron is famous as the birthplace of Thomas Edison (the most prolific inventor in American history — Thomas Alva Edison was born in Milan, Ohio, but grew up in Port Huron; Edison's boyhood home is a museum in Port Huron; Edison worked as a telegraph operator in Port Huron before moving to Detroit and eventually becoming the inventor of the phonograph, the practical incandescent light bulb, and the motion picture camera)), home of the Port Huron–Sarnia Blue Water Bridge (the international crossing connecting Port Huron, Michigan to Sarnia, Ontario — one of the busiest US–Canada border crossings in the Midwest), a diverse St. Clair County community with a significant German-American, Italian-American, and working-class manufacturing heritage population — draws its municipal water supply from Lake Huron via the City of Port Huron Water Treatment Plant. Water hardness in Port Huron measures 150.5 mg/L — classified as moderately hard.

Port Huron's moderate hardness reflects the east Michigan Lake Huron supply's calcareous-moderate character with limited softening. The Lake Huron at Port Huron draws dissolved carbonates from the Devonian Michigan Basin dolomite (calcareous). City of Port Huron applies limited softening, producing the moderate 150.5 mg/L.

At 150.5 mg/L, Port Huron residents encounter moderate scale accumulation. Monthly cleaning is recommended. City of Port Huron Water Treatment Plant consistently delivers water meeting all Michigan EGLE and EPA Safe Drinking Water Act requirements.