Enter your ZIP code. We pull regional water hardness data and tell you exactly what you're dealing with — and whether you can keep cleaning with tap water or need to switch to distilled.
US ZIP codes only. For the 271 covered cities: the utility's own published figure, as on the national rankings. Elsewhere: a planning estimate, labelled as one.
You are in the hardest band in North America. Phoenix, Las Vegas, parts of Texas and the upper Midwest. At this level, calcium carbonate precipitates out of any water that touches your glass and dries — the spots you see are essentially limestone, growing one molecular layer at a time. Tap water cannot be part of your final pass under any circumstance.