Water hardness / Nashville
Is Nashville water hard? Somewhat.
Somewhat. Nashville tap water measures 75.3 mg/L of hardness as calcium carbonate, which is moderately hard on the USGS scale. The figure is the average Metro Water Services publishes in its Metro Water Services, 2025 Water Quality Report.
Where Nashville sits on the scale.
Nashville's published average is 75.3 mg/L. On the USGS scale, that is moderately hard.
0–60Moderate
61–120Hard
121–180Very hard
180+
What it means for curly hair
At this level, mineral buildup is possible but usually slow. It matters more if your hair is bleached or damaged, because damaged hair takes up more calcium and magnesium (Evans, Marsh and Wickett, 2011).
Watch for the signs before changing your routine: curls that turn dull or stiff over a few weeks.
Hard water is a plausible factor, not a proven cause of breakage. Sudden shedding, itching, flaking or scalp pain needs a dermatologist, not a chelating routine.
Change less. Learn more.
What to try
No chelating routine is needed by default. If your curls turn dull or stiff, try one chelating wash and compare the next two wash days.
What to avoid
Do not clarify or chelate every wash: it strips more than minerals.
Do not blame the water for sudden shedding, itching, flaking or scalp pain. That is a reason to see a dermatologist.
Every number keeps its source.
63.9–92.6 mg/L; promedio 75.3 mg/L. Classified with the US Geological Survey bands (soft 0 to 60, moderately hard 61 to 120, hard 121 to 180, very hard above 180 mg/L). Period: 2025. Checked against the source on 2026-10-20. Rizzado did not measure this water.
The Metro Water Services report is public: Metro Water Services, 2025 Water Quality Report. Hardness can vary by area and season, and private wells or buildings with their own treatment can differ. If you want your exact value, ask the utility for your address.
Sources
- Metro Water Services, 2025 Water Quality Report
- Evans, A. O., Marsh, J. M., Wickett, R. R. (2011). The uptake of water hardness metals by human hair. Journal of Cosmetic Science, 62(4), 383-391.
- Luqman, M. W. et al. (2016). Effect of topical application of hard water in weakening of hair in men. Journal of the Pakistan Medical Association, 66(9), 1132-1136.
- Luqman, M. W. et al. (2018). To evaluate and compare changes in baseline strength of hairs after treating them with deionized water and hard water. International Journal of Trichology, 10(3), 113-117.
- Srinivasan, G., Srinivas, C. R., Mathew, A. C., Duraiswami, D. (2013). Effects of hard water on hair. International Journal of Trichology.
- U.S. Geological Survey. Hardness of water.
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RIZZADO
Your water is one part of the picture.
Rizzado uses your city's water hardness, when there is a primary source, to adjust your routine. If your city is not here, it treats the value as unknown.
