<p>In Michigan, mains water is delivered by local public water systems, regulated by the Michigan Dept of Environment, Great Lakes and Energy (EGLE), Drinking Water Division under the US EPA Safe Drinking Water Act. Typical hardness: Hard; groundwater high in calcium / magnesium, statewide avg ~188 ppm. For a specific ZIP, see the EWG Tap Water Database.</p>
Sources: Michigan Dept of Environment, Great Lakes and Energy (EGLE), Drinking Water Division, EWG Tap Water Database