We had a really good laugh about this one during lunch today, and I just had to share. One of my friends is getting a new fish tank and has been having problems getting the fish to survive. Her dad used one of those test kits and found that their water was hard. (It hadn’t gotten the sediments and minerals taken out of it by the water softener.) So, my friend starts wiggling her fingers around in the tank, and her dad asks what she’s doing. She told him that she didn’t see how the water could be hard. 
Today we explained to her what hard water meant.
BTW: She is actually blonde.
That’s funny. I know what hard water is, but I can’t say I know why someone picked the word “hard” to describe it—is it just that minerals are hard when they are rocks?
Oh, and remember, blondes have more fun! 
It’s ice isn’t?
MarkB
I may take this memory to my grave…
… in grade school, we had an art teacher who was noticeably laughing while looking at a plastic ice cream container (we’d brought them in for a project of sorts).
“Isn’t this funny,” she says…“It says here on this container, 16 fluid ounces. Everyone knows that ice cream is a solid.”
She was pretty embarrassed when a 10 year old had to explain to her how the ice cream got into the carton to begin with…
It’s called that because “hard water” is “hard” to wash clothes in, because calcium and magnesium bond with soaps, making curds instead of suds.
(ie: hard as in ‘difficult’ not as in ‘solid’)
If this seems silly, bear in mind that “right whales” are named that because they’re the “right whale” for hunting.
The water-softener literature from various companies which I reviewed with my folks a while back (they were looking into getting a water-softening unit) mostly claimed that the water was called “hard” because the minerals (esp. calcium and magnesium, as you noted) leave hard scale behind as the water evaporates. So you get those cloudy glasses and shower doors, etc.
Could go either way, but I find the “hard mineral deposits” story more plausible than the “hard to make soap lather” tale. But who knows?
Doesn’t Thumper say something like “C’mon in, Bambi, the water’s hard!” during the ice-sliding scene in “Bambi”? Golly, hadn’t thought of that movie in years and years. . .
The “hard to make lather” tale does seem implausible. But then again, so does the “right whale” tale.
The EPA says it’s because of the lather. That’s good enough for me 
http://www.tulsawater.com/edu_online_waterqa.html
(the the Tulsa water authority is easier to quote..but ou can find it directly on the EPA site here)
Source: U.S. Environmental Protection Agency
From: Plain Talk About Drinking Water: Questions and Answers About the Water You Drink by Dr. James M. Symons, published by American Water Works Association.
Q. What is “hard” water?
A. The answer may surprise you. Hardness in drinking water is caused by two nontoxic chemicals-usually called minerals - calcium and magnesium. If either of these minerals is present in your water in substantial amounts, the water is said to be “hard,” because making a lather or suds for washing is “hard” (difficult) to do. Thus cleaning with hard water is difficult. Water containing little calcium or magnesium is called “soft” water. (Maybe it should be called easy, the opposite of difficult.) Water that does not contain enough calcium or magnesium may be “too soft.”
Other websites that make the “lather” claim:
http://www.answers.com/hard%20water
http://www.saskschools.ca/curr_content/science10/unita/redone9.html
http://www.snwa.com/html/wq_water_facts_hardwater.html (Southern Nevada Water Authority)
etc.
Now, granted, your explanation sounds equally plausible, so I’m not trying to prove ya wrong..I just didn’t want anyone think I was just makin things up
I think someone in the EPA is a bit…strange. The opposite of hard water should be “easy” water, then, by that reasoning.
You posted while I was revising…I could proably find a score of water authorities that call it “hard” due to the difficulty making lather.
The soft water thing isn’t so difficult to figure out, considering that english is not a logical language…
For instanace, if the term “hard water” came into colloquial use, but there was no term for it’s opposite (just as there is no “wrong whale” or “left whale”). There was “water” and “hard water”…
Then later, companies made products to remove the chemicals. What would they call those products? “Water Easiers”? Water softeners would make good marketing sense.
Now, granted, I’m not saying that this is how things went..but it sure could have been how things went. I find both explanations plausible.
Oh sure, go choose a few clearly biased news sources to support your communist (or maybe far-right-wing) views on the subject of water hardness while ignoring all of my flawlessly-reasoned and superiorly-reported conclusions, while winkingly maligning my patriotism and insulting my mother, who I’ll have you know . . .
Oh, wow. I started channeling IRTradRU and JGilder at the same time. Believe me, you do not want that going on in your head.
(I kid. I kid because I love.)
I didn’t think you were making things up at all. I AM of the opinion that whoever, in defining “difficulty” as the official EPA stance on the meaning of “hard”, is thinking in a strange manner, or the whole EPA spinmeister cadre is off its collective rocker. I know from hard water: yellowish, irony, sulphurous stinky stuff that you could just about chew on from South Dakota artesian wells. You couldn’t get a more distinctive cup of coffee. Nobody I knew ever suggested that hard water was named for its lather-killing properties; it was always about heavy mineral content, as if the water was practically stone itself. But that’s just us benighted Great Plains barbarians. To be honest, it’s all about usage, and I think the EPA’s explanation is just as capable of being as fallacious as any other.
And I knew about Right Whales. Whatever else we lacked, we had decent educations out there in the flatlands.
As I recall, water softeners can be the problem. They can leave stuff behind in the water, like salt, which is death to fishies.
The tap water here, which comes from a limestone aquifer spring a bit north of here, is so hard that it leaves a white powdery residue if you allow a bit to dry in the bottom of a glass. Well water is even worse, having so much iron and sulfur that it stains everything rust. And reeks of rotten eggs.
It really is more difficult to wash clothes, and yourself, in hard water. Old-fashioned “soap” soap doesn’t really suds, but simply turns into this fluffy gray curd stuff that adheres to everything–like dried-out hair mousse. You can feel it on your skin like a plastic-grease layer. It makes nightmare bathtub rings. It will clog drains. White clothes turn gray and darks get a white frosting.
That’s why Zest was advertised as leaving no tub ring–it was a detergent when everything else was a soap, so it didn’t curd up in the water.
These days, you often don’t notice the sudsing problem, because manufacturers reformulate products according to the water in the areas where they will be sold. If you buy a bar of soap made in Scotland, though, and try to use it here, you’ll quickly discover what all the fuss was about.
Good one, gotta admit!
For instanace, if the term “hard water” came into colloquial use, but there was no term for it’s opposite (just as there is no “wrong whale” or “left whale”). There was “water” and “hard water”…
Then later, companies made products to remove the chemicals. What would they call those products? “Water Easiers”? Water softeners would make good marketing sense.Now, granted, I’m not saying that this is how things went..but it sure could have been how things went. I find both explanations plausible.
“Software” had exactly such a genesis.
You describe our water here exactly- all of the above and the lime sticks to everything particularly all the water faucets and anything glass and is a constant battle to remove. Oh and I was told by a doctor that we are much more prone to kidney stones around here because of the combination of the extreme mineral content of the water and the Scots Irish genes. 
My mother-in-law never used any other soap than Zest because it worked better in the water here. Hopefully, we will get rid of this aspect of our water sometime this summer as our major house restoration gets under way- a water treatment thingy of some kind is high on the list.
Lots of species of fish prefer hard water, so it may not be the water that’s killing them.
Has she done a fishless cycle before she added the fish?
A person has to cycle the tank (which involves more than just putting water in a tank then adding fish) for a few weeks before adding fish, or they will die from high ammonia levels, not hard water.
Well…somebody had to!
Slan,
D.
Dubhlinn to the rescue.
We have a good water softener but last two weeks ago my wife made coffee and it tasted like it had been made in seawater. As it turned out there was a clog in the little hose that ran from the softener tank to the salt reservoir. That cost me $70.00 to find out!!1
Our water is so iron rich you could built a battleship from it.
The OED can always shed some light:
- a. Applied to water holding in solution mineral, especially calcareous, salts, which decompose soap and render the water unfit for washing purposes.
1660 F. BROOKE tr. Le Blanc’s Trav. 18 The water was sharp and hard, but nothing brackish. 1756 C. LUCAS Ess. Waters I. 83 Hard waters are the best for builders and plasterers. 1805 W. SAUNDERS Min. Waters 305 A very hard water, curdling soap, and possessing a large portion of selenite and earthy carbonats. 1849 R. T. CLARIDGE Cold Water-cure (1869) 85 Hard water makes the skin rough, but soft water, on the contrary, renders it smooth.
It looks as though “hard to lather” is the right idea, but not refering to washing things. Based on the given usages of “hard water” it seems that “hard” means “hard on the skin.” Given that non-hard water is “soft,” this seems quite plausible.
And “hard” as in difficult seems silly, not the least because the word is an adverb in that case…