Guide
How to tell whether your water is hard
Most of the signs people are told to look for are real. A few are not, and one of them sells a lot of unnecessary equipment. Here is how to check properly for nothing.
The signs that are reliable
White crust on the kettle element, the shower head and around tap outlets. This is calcium carbonate coming out of solution when water is heated or evaporates, and it is the most direct visible evidence there is.
Soap that will not lather, and a film left on skin after a shower. Hardness minerals react with soap to form a residue instead of foam, which is why hard water areas get through more detergent for the same result.
Spots and streaks on glassware after a dishwasher cycle, which are mineral deposits left when droplets dry. And a water heater that has become noisy or is heating less efficiently than it did, because scale has built up on the element.
The signs that are misleading
Cloudy or white water from the tap that clears from the bottom upward is almost always dissolved air, not minerals. Fill a glass and let it stand. If it clears, it was air, and no amount of treatment will change it because there is nothing there.
A chlorine or chemical taste is not hardness. Those are two unrelated properties of the water, they need different equipment, and a softener will not change the taste. This is a common and expensive confusion.
Orange or brown staining is iron rather than hardness, and rotten egg smell is hydrogen sulfide. Both are frequently sold as reasons to buy a softener. A standard softener is not the right tool for either, though some are configured to handle low levels of iron.
Get an actual number, for free
Every public water system publishes an annual report, and hardness is usually in it. That figure costs nothing and is more reliable than any inference from your kettle. It describes the system rather than your tap, but for hardness the difference is rarely material because minerals do not appear or vanish in the last hundred feet of pipe.
Hardness is reported either in grains per gallon or in milligrams per litre as calcium carbonate. To convert, divide milligrams per litre by 17.1. So 250 mg/L is 14.6 grains per gallon.
The scale most of the trade uses: under 3.5 grains per gallon is soft, 3.5 to 7 is moderately hard, 7 to 10.5 is hard, and above 10.5 is very hard.
Why a regional figure is not good enough
Hardness varies more within a single town than most people expect, because it is a property of the source rather than the region. A town drawing on two different sources can have two different hardness figures at the same time.
Manchester in Connecticut is the clearest example in our coverage. Water from its Globe Hollow plant is moderately hard, while the New State Road and Love Lane well areas run around 250 mg/L, which is 14.6 grains per gallon. Same town, and a softener is close to pointless at one end and overdue at the other.
The general rule holds across the region: groundwater is harder than surface water, because water moving slowly through mineral deposits dissolves calcium and magnesium out of them. Upland reservoir supplies tend to be soft.
When hard water is worth treating, and when it is not
The honest economic case for softening is the water heater. Scale on a heating element makes it work harder and shortens its life, and over the fifteen years of a heater the saving is real at genuinely hard levels.
Below about 7 grains per gallon that case gets thin. Spotted glassware is annoying rather than costly, and rinse aid solves it for a few dollars a year. We would rather tell you that than sell you equipment.
Hardness is also not a health problem. Calcium and magnesium are not harmful in drinking water, and there is no health standard for hardness because none is needed. Anyone selling you a softener on health grounds is selling you something else.
Common questions
Is hard water bad for you?
No. Calcium and magnesium are not harmful to drink, which is why there is no federal or state health limit for hardness. It is classed as an aesthetic and practical issue rather than a health one. The costs of hard water are scale in appliances, extra detergent and spotted dishes, and those are the honest reasons to treat it.
My water looks cloudy. Is that hardness?
Usually not. Fill a glass and leave it on the counter. If the cloudiness clears from the bottom upward within a minute or two, it was dissolved air, which is harmless and untreatable because there is nothing in the water to remove. Hardness does not make water look cloudy in the glass. It shows up as deposits on surfaces after water has evaporated or been heated.
Can I test hardness myself?
Yes, and a strip kit costs very little, but check your utility's annual report first because the figure is probably already published. A home test is most useful when you are on a private well, where nobody publishes anything, or when you want to confirm a figure at your own tap before sizing equipment.
Related reading
- water problems: hard water
- water filters: water softeners
- guides: water softener vs salt free conditioner
Other guides
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