The Almanac 路 Diagnosis

How to Test Your Water at Home (For Your Hair, Not Your Plumbing)

Growing SZN Research Desk 路 September 14, 2026
Quick answer Run your shower for thirty seconds, catch the water in a clean glass, dip a total hardness strip for one second, hold it level, and read it against the chart after the time on the packet. You want a number in ppm of calcium carbonate. Test the shower, not the kitchen tap, because the shower is the water your hair actually meets.

Search how to test your water at home and you will get plumbers, water softener companies and people worried about what they are drinking. That is a different question from the one you are asking. You want to know what the water is doing to your hair, and almost nobody is answering that version.

Test the shower, not the kitchen

This sounds pedantic and it is not. Kitchen taps are the most likely place in a house to have a filter on them, whether that is a pitcher, a fridge line or an under-sink unit. Your shower almost never does. If you test filtered kitchen water and conclude your water is fine, you have tested the one tap your hair never touches.

Run the shower for about thirty seconds first so you are sampling what comes through the pipe rather than what has been sitting in it overnight.

The three ways to test, ranked honestly

1. A total hardness strip. The right tool for this job. One second in the water, read after the time printed on the packet, usually thirty to sixty seconds. It gives you a band in ppm, and a band is all the decision needs. Strips read calcium and magnesium; they do not read iron, copper or chlorine, which matters if you are on a well.

2. The soap shake test. Free. Half fill a clear bottle, add a few drops of plain liquid soap, cap it and shake. Lots of stable foam and clear water underneath means soft. Thin foam that collapses, with cloudy water, means hard. It will tell you roughly where you sit and it will never give you a number, which means it cannot tell you how often to treat. Use it as a first look.

3. Your utility's annual report. Free and often useless for this. Hardness is not a regulated contaminant in the United States, so plenty of utilities simply do not print it. Miami-Dade is the example we went through in detail: the report describes lime softening at the plants and gives no hardness figure at all. When the report is silent, your own shower is the only number that applies to you.

Reading the number

Reading (ppm CaCO3)BandWhat it means for hair
0 to 60SoftBuildup is unlikely to be your problem. Look at heat, bleach and tension first.
61 to 120Moderately hardBuildup accumulates slowly. Occasional treatment is usually enough.
121 to 180HardDeposits build fast enough to notice between washes.
181 and upVery hardThe most common band for "my hair changed when I moved" stories.

Bands follow the standard USGS hardness classification. We covered what each one means for treatment frequency in how often you should actually treat.

The part that makes the number less absolute than it looks. Evans, Marsh and Wickett (2011) found that how much metal a hair takes on is driven mostly by the condition of the hair itself rather than by how hard the water is. Bleached and damaged hair binds substantially more. Hardness level, in their words, "had only a small effect on uptake." So two people on identical water can genuinely need different routines, and the strip tells you about your water while your mirror tells you about your hair. Read both.

"Aren't test strips a scam?"

It is a fair question and it gets asked constantly, so here is the honest version. A hardness strip is a colour comparison. It gives you a band, not a laboratory measurement, and anyone selling one as lab-grade precision is overselling it.

The thing is, a band is the whole decision. You are not trying to know whether your water is 138 or 151. You are trying to know whether it is soft, moderate, hard or very hard, because that is what changes what you do. For that, a strip is genuinely sufficient.

Where strips are the wrong tool: regulated contaminants. If you are worried about lead, do not use a strip, use a certified lab test. Different question, different instrument.

What to do with the answer

If you read soft, mineral buildup is probably not your story, and chasing it will waste your money. Go look at heat and processing instead.

If you read hard or very hard and your hair is stiff, dull, tangling more than it used to, or snapping without a root bulb on the fallen strands, the number and the symptom agree. That is the point of testing: it either confirms the suspicion or it frees you to stop blaming the wrong thing. Our bulb test takes ten seconds and tells you whether you are looking at breakage or normal shedding, which is the other half of the diagnosis.

And if you have been told you have protein overload, test your water before you rebuild your routine around protein. The two conditions feel identical and the fixes are opposite.