What Is Hard Water, and Do You Need a Water Softener?

Hard water is water that carries a lot of dissolved calcium and magnesium. It is not a health risk. It leaves soap curd on your skin, spots on your glasses and scale in your pipes. Minnesota Health says there is no rule that you must soften it. It also says that above 7 grains per gallon, or 120 mg/L, you might need a softener.

Water picks it up on the way to your tap. Nebraska Extension says water is a good solvent. As it moves through soil and rock, it dissolves tiny amounts of minerals and holds them.

Two minerals matter most. Nebraska Extension names calcium and magnesium as the two that make water hard. The more of them your water carries, the harder it is.

Penn State says the same. Whether your water is called hard or soft comes down to those two.

Nebraska Extension lists them, and they read like a list of small daily annoyances.

Soap is the first one. Soap used in hard water joins the minerals and forms a sticky curd. Some detergents work less well, because the hardness knocks out part of the active ingredient.

Then your skin. Nebraska Extension says bathing in hard water leaves a film of that curd on the skin. It says the film may stop soil and bacteria coming off. The curd also gets in the way of skin returning to its normal, slightly acid state, and that may lead to irritation.

Your hair shows it too. Nebraska Extension says soap curd on hair may leave it dull, lifeless and hard to manage.

Laundry is next. Curds lodge in the fabric while it washes. Nebraska Extension says that makes fabric stiff and rough. White items gray, colors lose brightness, and a sour smell can build up. It says washing in hard water over and over can shorten the life of clothes.

Then the hardware. Curd lands on dishes, tubs, showers and fixtures. Heated hard water forms scale. Nebraska Extension says that scale can make water using appliances run poorly or fail. Pipes can clog with scale, which cuts the flow and can end in a pipe replacement.

The federal chart agrees. The EPA lists scaly residues and soaps that do not lather as the sign to test for hardness.

Two sources give you the same line to stand on.

Minnesota Health says there is no requirement to soften your water. It calls the decision a personal choice that affects your home and the environment. Then it gives the number. Your hardness may be greater than 7 grains per gallon, or 120 mg/L. Above that, it says, you might need a softener. The reasons it gives are keeping appliances running well and improving the taste, smell or look of your water.

Penn State draws the line in the same place. It says levels below 7.0 grains per gallon will probably not cause major scaling and soap film.

Penn State's own table names that band. Water from 7.0 to 10.5 grains per gallon is hard. Above 10.5, it is very hard.

So the honest rule is short. Under 7 grains, live with it. Over 7 grains, a softener has a job to do.

No. Nebraska Extension says hard water is not a health hazard.

It goes further. It cites the National Research Council. Hard drinking water adds a small amount of calcium and magnesium toward what the diet needs.

Penn State agrees. It calls calcium and magnesium essential daily nutrients with no bad effects on health.

The health question actually points the other way. Softening puts sodium in. Nebraska Extension says the trade adds about 8 mg/L for each grain per gallon removed. Water at 10 grains per gallon holds about 80 mg/L of sodium once it is soft.

Some people are told to skip it. Nebraska Extension says a doctor may advise against a softener. The advice may also be to soften only the hot water. Another option is a cold line that runs around the unit to the kitchen tap.

Minnesota Health publishes both sides, which is rare and useful.

The wins are the ones you would expect. Softening stops scale inside pipes, fixtures and water heaters. It lengthens the life of some appliances. It cuts mineral spots on glassware. It stops soap films and curds in sinks, tubs and washing machines.

The costs are real too. Minnesota Health says a softener can corrode your pipes, and that the metal from those pipes can end up in your water. That can raise lead and copper levels. It names the extra sodium as a health point to weigh. It says you need to test the water and maintain the unit for it to work right. It also names the salt going into the environment, and the waste water from each cleaning cycle.

That water use has a number on it. Penn State says about 50 gallons are used for each cleaning cycle. If you own a septic system, Penn State says to think about that extra load on the drainage field.

If your water comes from a community system, call them first.

Minnesota Health says to check whether your community already softens the water. Soft water from a utility does not need more softening, and doing it anyway may cause corrosion in your home.

Two more setup notes come from the same page. Set the softener to the hardness of your supply. If the setting is too high, the unit costs more to run and wastes water, which costs you money. And if your home has new copper plumbing, do not run a softener for the first few weeks. That lets the pipes form a protective mineral layer.

Start with the number, not the sales visit.

Minnesota Health says you can measure hardness with a test kit or an independent lab. If you are on a community system, you can contact them directly and ask.

Then decide how much of the house needs it. Penn State says that unless your water is extremely hard, not all the incoming water needs to be softened. Showers, sinks and laundry hookups probably should be. Toilets, outside spigots and basement sinks can be bypassed.