Water described as "hard" is high in dissolved minerals, specifically calcium and magnesium. Hard water is not a health risk, but a nuisance because of mineral buildup on fixtures and poor soap and/or detergent performance.
Water is a good solvent and picks up impurities easily. Pure
water -- tasteless, colorless, and odorless -- is often called
the universal solvent. When water is combined with carbon dioxide
to form very weak carbonic acid, an even better solvent results.
As water moves through soil and rock, it dissolves very small
amounts of minerals and holds them in solution. Calcium and
magnesium dissolved in water are the two most common minerals
that make water "hard." The degree of hardness becomes
greater as the calcium and magnesium content increases.
Hard water interferes with almost every cleaning task, from
laundering and dishwashing to bathing and personal grooming.
Clothes laundered in hard water may look dingy and feel harsh and
scratchy. Dishes and glasses may be spotted when dry. Hard water
may cause a film on glass shower doors, shower walls, bathtubs,
sinks, faucets, etc. Hair washed in hard water may feel sticky
and look dull. Water flow may be reduced by hard water deposits
Dealing with hard water problems in the home can be a
nuisance. The amount of hardness minerals in water affects the
amount of soap and detergent necessary for cleaning. Soap used in
hard water combines with the minerals to form a sticky soap curd.
Some synthetic deter- gents are less effective in hard water
because the active ingredient is partially inactivated by
hardness, even though it stays dissolved.
Bathing with soap in hard water leaves a film of sticky soap
curd on the skin. The film may prevent removal of soil and
bacteria. Soap curd interferes with the return of skin to its
normal, slightly acid condition, and may lead to irritation. Soap
curd on hair may make it dull, lifeless and difficult to manage.
When doing laundry in hard water, soap curds lodge in fabric
during washing to make fabric stiff and rough. Incomplete soil
removal from laundry causes graying of white fabric and the loss
of brightness in colors. A sour odor can develop in clothes.
Continuous laundering in hard water can shorten the life of
In addition, soap curds can deposit on dishes, bathtubs and
showers, and all water fixtures.
Hard water also contributes to inefficient and costly
operation of water-using appliances. Heated hard water forms a
scale of calcium and magnesium minerals that can contribute to
the inefficient operation or failure of water-using appliances.
Pipes can become clogged with scale that reduces water flow and
ultimately requires pipe replacement.
Hard water is not a health hazard. In fact, the National
Research Council (National Academy of Sciences) states that hard
drinking water generally contributes a small amount toward total
calcium and magnesium human dietary needs. They further state
that in some instances, where dissolved calcium and magnesium are
very high, water could be a major contributor of calcium and
magne- sium to the diet.
Researchers have studied water hardness and cardiovascular
disease mortality. Such studies have been "epidemiological
studies," which are statistical relationship studies.
While some studies suggest a correlation between hard water
and lower cardiovascular disease mortality, other studies do not
suggest a correlation. The National Research Council states that
results at this time are inconclusive and recommends that further
studies should be conducted.
If you are on a municipal water system, the water supplier can
tell you the hardness level of the water they deliver. If you
have a private water supply, you can have the water tested for
hardness. Most water testing laboratories offer hardness tests
for a fee, including the Nebraska State Department of Health
Laboratory. The NebGuide G89-907, Water Testing Laboratories,
lists additional certified water testing facilities in Nebraska.
Many companies that sell water treatment equipment offer
hardness tests. When using these water tests, be certain you
understand the nature of the test, the water condition being
measured, and the significance of the test results.
An approximate estimate of water hardness can be obtained
without the aid of outside testing facilities. Water hardness
testing kits are available for purchase through water testing
supply companies. If more accurate measurements are needed,
obtain a laboratory test.
The hardness of your water will be reported in grains per
gallon, milligrams per liter (mg/l) or parts per million (ppm).
One grain of hardness equals 17.1 mg/l or ppm of hardness.
The Environmental Protection Agency (EPA) establishes
standards for drinking water which fall into two categories --
Primary Standards and Secondary Standards.
Primary Standards are based on health considerations and
Secondary Standards are based on taste, odor, color, corrosivity,
foaming, and staining properties of water. There is no Primary or
Secondary standard for water hardness.
Water hardness is classified by the U.S. Department of
Interior and the Water Quality Association as follows:
(Other organizations may use slightly different classifications)
mg/l or ppm
0 - 17.1
0 - 1
17.1 - 60
1 - 3.5
60 - 120
3.5 - 7.0
120 - 180
7.0 - 10.5
180 & over
10.5 & over
Water Hardness Test Kits-
your water stands to determine your strategy.
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hardness in Grains.
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your softener's efficiency!
Here for details!
There are two ways to help control water hardness: use a
packaged water softener, or use a mechanical water softening
Packaged water softeners are chemicals that help control
water hardness. They fall into two categories: precip-itating and
Precipitating water softeners include washing soda and borax.
These products form an insoluble precipitate with calcium and
magnesium ions. The mineral ions then cannot interfere with
cleaning efficiency, but the precipitate makes water cloudy and
can build up on surfaces.
Precipitating water softeners increase alkalinity of the
cleaning solution and this may damage skin and other materials
Non-precipitating water softeners use complex phosphates to
sequester calcium and magnesium ions. There is no precipitate to
form deposits and alkalinity is not increased.
If used in enough quantity, non-precipitating water softeners
will help dissolve soap curd for a period of time.
Mechanical water softening units can be permanently installed
into the plumbing system to continuously remove calcium and
Water softeners operate on the ion exchange process. In this
process, water passes through a media bed, usually sulfonated
polystyrene beads. The beads are supersaturated with sodium. The
ion exchange process takes place as hard water passes through the
softening material. The hardness minerals attach themselves to
the resin beads while sodium on the resin beads is released
simultaneously into the water.
When the resin becomes saturated with calcium and magnesium,
it must be recharged. The recharging is done by passing a salt
(brine) solution through the resin. The sodium replaces the
calcium and magnesium which are discharged in the waste water.
Hard water treated with an ion exchange water softener has
sodium added. According to the Water Quality Association (WQA),
the ion exchange softening process adds sodium at the rate of
about 8 mg/liter for each grain of hardness removed per gallon of
For example, if the water has a hardness of 10 grains
per gallon, it will contain about 80 mg/liter of sodium after
being softened in an ion exchange water softener if all hardness
minerals are removed.
Because of the sodium content of softened water, some
individuals may be advised by their physician, not to install
water softeners, to soften only hot water or to bypass the water
softener with a cold water line to provide unsoftened water for
drinking and cooking; usually to a separate faucet at the kitchen
Softened water is not recommended for watering plants, lawns,
and gardens due to its sodium content.
Although not commonly used, potassium chloride can be used to
create the salt brine. In that case potassium rather than sodium
is exchanged with calcium and magnesium.
Before selecting a mechanical water softener, test water for
hardness and iron content. When selecting a water softener, the
regeneration control system, the hardness removal capacity, and
the iron limitations are three important elements to consider.
There are three common regeneration control systems. These
include a time-clock control (you program the clock to regenerate
on a fixed schedule); water meter control (regenerates after a
fixed amount of water has passed through the softener); and
hardness sensor control (sensor detects hardness of the water
leaving the unit, and signals softener when regeneration is
Hardness removal capacity, between regenerations, will vary
with units. Softeners with small capacities must regenerate more
Your daily softening need depends on the amount of water used
daily in your household and the hardness of your water. To
determine your daily hardness removal need, multiply daily
household water use (measured in gallons) by the hardness of the
water (measured in grains per gallon).
Example: 400 gallons used per day X 15 grains per
gallon hardness = 6,000 grains of hardness must be removed daily.
Iron removal limitations will vary with water softener units.
If the iron level in your water exceeds the maxi- mum iron
removal capacity recommended by the manufacturer of the unit you
are considering, iron may foul the softener, eventually causing
it to become plugged. For additional information on water
softeners, including information on how a water softener works,
maintenance requirements of water softeners, difference in
softener salt, etc. See NebGuide G89-946, Water Treatment
Equipment: Water Softeners.
Hard water is not a health hazard, but dealing with hard water
in the home can be a nuisance. The hardness (calcium and
magnesium concentration) of water can be approximated with a
home-use water testing kit, or can be measured more accurately
with a laboratory water test. Water hardness can be managed with
packaged water softeners or with a mechanical ion exchange