Hardness is not a yes or no, it is a number in a band, and you can find yours three ways: read the deposits your fixtures are already showing you, dip a test strip for a fast band, or get a lab or utility figure precise enough to size equipment. Do the cheap ones first, and only pay for the last one when you are actually buying.
What the fixtures are telling you
Chalky white scale around shower nozzles, on tap spouts and inside a kettle is dissolved mineral left behind as water evaporates, and it is the most reliable free evidence there is. So is a glass shower screen that clouds within days of cleaning, and glassware that comes out of the dishwasher filmed rather than clear. If a heating element in a kettle is crusted white within months, you are in the upper bands and you do not need a test to know it.
Test strips and what they do and do not give you
A hardness strip dipped in cold tap water changes color in seconds and puts you in a band. That is enough to answer the question and enough to decide whether to go further. It is not precise enough to size a softener, and strips read the water at that tap on that day, so test a cold tap that has run for a minute rather than a first draw that has been sitting in the pipe overnight.
The number that actually matters
Hardness is dissolved calcium and magnesium, and the USGS classifies water as soft at 0 to 60 mg/L as calcium carbonate, moderately hard at 61 to 120, hard at 121 to 180 and very hard above that. Equipment suppliers usually quote grains per gallon instead of milligrams per liter, so check which unit a quote uses before comparing two of them. A utility report or a lab result gives you a figure either way.
Do not confuse hardness with everything else
Orange or brown staining is iron, black specks are manganese, a rotten egg smell is sulfide, and cloudy water is usually air or sediment. None of those are hardness, and a softener is the wrong machine for most of them. If your complaint is staining or smell rather than scale and poor lather, our well water testing guide covers the panel to order so you treat the right thing the first time.
Questions people ask about how to tell if water is hard
Can I tell if water is hard without a test?
Often yes. White scale on fixtures, a clouding shower screen, poor lather and filmy glassware together are strong evidence of hard water.
Are hardness test strips accurate enough?
They place you in a band reliably, which answers the question. Sizing a softener needs a precise figure from a lab or your utility report.
Does a TDS meter measure hardness?
No. It estimates total dissolved solids from conductivity and cannot separate calcium and magnesium from sodium, chloride or anything else.
Is hardness a health concern?
It is treated as an aesthetic and practical issue: scale, soap use and appliance life. The reason to treat it is cost and comfort, not safety.