Guides

• How HardnessCheck Measures Your County's Water Hardness — The exact source, filters and summary statistic behind every county's hardness figure, and why we report the median of site medians.
• Grains per Gallon vs mg/L: Reading Any Hardness Number — Convert a utility report, test strip or dishwasher setting between gpg, mg/L and ppm, and see where each number falls on the softener decision scale.
• What Size Water Softener Do You Need? — Size a softener from your hardness and household, with the arithmetic shown, and why the most common mistake is buying too small.
• Well Water vs City Water: Why Hardness Differs Next Door — In 1,515 of 2,143 counties with both, wells measure harder than rivers and lakes. What that means for your tap.
• When You Do Not Need a Water Softener — In 740 US counties the water is already soft. How to tell, what hard water does and does not do, and what a softener really costs.