Hard water build-up comes from naturally occurring minerals — such as calcium bicarbonate, magnesium carbonate, iron, lime and others — that are present in lakes and other water sources across North Texas. The treated water supplied by NTMWD is considered “moderately hard” primarily due to the minerals found in Lavon Lake.

While these minerals pose no harm to human health or safety, they can cause spots on clean dishes and “lime scale” on plumbing fixtures from the leftover mineral deposits once hard water has evaporated. You may want to seek guidance from a licensed plumber about maintaining plumbing fixtures and water heaters which can build up with hard water mineral deposits over time.

To determine the grains per gallon of hardness of your water, refer to our water quality reports and divide the total hardness (mg/L) by 17.12. The hardness is also measured by the Total Dissolved Solids (TDS) on water quality reports. Read the hard water fact sheet for more information.

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NTMWD-WaterHardness Fact Sheet 12-11-2018