Water hardness / Los Angeles
Is Los Angeles water hard? In many areas, yes.
In many areas, yes. Los Angeles tap water measures 112 to 272 mg/L of hardness as calcium carbonate, which is moderately hard to very hard on the USGS scale. The Los Angeles Department of Water and Power (LADWP) publishes a separate average for each water source or service zone in its 2024 Drinking Water Quality Report; the figure spans those averages, so your tap depends on which one serves your area. LADWP blends these sources differently by neighborhood and season.
Where Los Angeles sits on the scale.
Los Angeles's published range of source averages is 112 to 272 mg/L. On the USGS scale, that is moderately hard to very hard.
0–60Moderate
61–120Hard
121–180Very hard
180+
What it means for curly hair
Calcium and magnesium from hard water settle on the hair. Lab work shows hair takes up a limited amount of these minerals, and damaged or bleached hair takes up more than healthy hair (Evans, Marsh and Wickett, 2011).
The evidence on breakage is mixed: two small studies found lower strength after repeated hard-water rinses (Luqman et al., 2016 and 2018), while an earlier one found no clear difference (Srinivasan et al., 2013). So hard water is a likely factor, not a proven cause.
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
A city number is context, not a diagnosis. If a change began after a new water source, compare one wash with a product labelled for mineral deposits and keep the rest of your routine the same.
Change one thing at a time and compare the next two or three wash days. The effect of a specific formula is not guaranteed.
If your hair is bleached or color-treated, go slowly and stop if the experiment leaves it feeling less manageable.
What to avoid
Do not turn one experiment into a fixed routine without a consistent reason to keep it.
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.
Table III, Hardness, Total (as CaCO3), average by source: 112 (Los Angeles Aqueduct Filtration Plant), 122 and 142 (combined wells), 272 and 270 (MWD plants), 148. 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: 2024. Checked against the source on 2026-10-16. Rizzado did not measure this water.
The the Los Angeles Department of Water and Power (LADWP) report is public: 2024 Drinking 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
- 2024 Drinking 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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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.
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