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Get Informed | Hardness

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.

What is Hardness?

When explaining hardness to the public, in some ways it is easier to say what hardness is not than what it is. Having hardness in your water is not bad, not toxic, does not mean you have elevated levels of Lead, Arsenic, or other dangerous minerals. It does not mean that your water will clog your piping with scale. The total hardness of the water is typically expressed or reported as the equivalent of concentration of calcium carbonate in water as mg CaCO3/L or reported as "grains per gallon" (gpg). (Note: 1 grain per gallon is 17.12 mg CaCO3/L). The only problem is that with this expression some individuals think that hardness is just the amount of calcium carbonate in the water. Calcium carbonate is composed of a cation (Ca++) (positive 2) and an anion (CO3--) (negative 2). The hardness of the water is related to the cation concentration and not the anion and it is not just "Calcium".

Cations have a charge that is positive and the charge can be +1 or higher. The total hardness of the water is actually the measure of the cations with a charge of 2 or more, i.e., "multivalent positively charged cations. This would include cations such as: calcium, magnesium, Iron, Manganese, Barium, Strontium, Aluminum, etc, but would not include the cations with a positive charge of 1 like Sodium, potassium, and Lithium.

The total hardness of the water can be described as the combination of temporary (carbonate hardness) and permanent hardness (non-carbonate hardness). Temporary hardness is the hardness that is associated with anions like carbonate, bicarbonate, and hydroxide (OH-) because when the water is heated and ultimately boiled the water will lose some of the carbonate as CO2 and the solution will become supersaturated with multivalent cations which will begin to form particles and precipitate from the water as a carbonate scale. This scale is typically white or gray, but may have other colors depending on the cation and can easily be removed by dissolving them in vinegar (a weak acid). Permanent hardness is the hardness that is associated with non-carbonate anions, like Chloride, Sulfate, and Nitrate.

The primary source of hardness in most drinking water is from natural sources. Water is a good solvent and picks up impurities easily. Pure water -- tasteless, colorless, and odorless -- is often called the universal solvent (not really true but it does dissolve many things). When water is combined with carbon dioxide from our atmosphere it forms a very weak carbonic acid, which is an even better solvent. As this water moves through soil and rock, it dissolves very small amounts of minerals and holds them in solution. Typically, it is calcium and magnesium dissolved in water that make water "hard." The degree of hardness becomes greater as the amount of divalent or multivalent cations dissolved in the water increases.

How Does Hardness Become a problem?

Hardness can pose a potential problem if it is too low or too high. If the water hardness is too low, such as < 50 mg/L, the water may be corrosive to metal piping, fixtures, and appliances. If the hardness is high, it is possible for the multivalent cations to react with the carbonates in the water to produce chemical precipitates or "soap scum".

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 detergents 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 can leave a film on the skin that may prevent or inhibit the removal of "dirt", dead skin cells, oils, and bacteria. This film can also prevent the skin from returning to a more typical slightly acidic condition, i.e., pH 4 to about 6.5, and therefore result in irritation or possibly eczema. This film can also make hair look dull, lifeless, difficult to manage, and even make it feel dirty.

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. Because of incomplete cleaning, the clothes may get a sour odor and continuous laundering in hard water can shorten the life of clothes. The soap curds can deposit on dishes, bathtubs and showers, and all water fixtures, contributing to nuisances.

What are the Health Risks for Hardness?

Hard water is not a health hazard. The National Academy of Sciences states that drinking hard water contributes to the dietary need for calcium and magnesium. 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 such a correlation. The National Research Council states that results at this time are inconclusive and recommends that further studies should be conducted.

Solid Report on this Issue - Suggested reading (Source) - a few quotes:

"The impact of water hardness of urinary stone formation remains unclear, despite a weak correlation between water hardness and urinary calcium, magnesium, and citrate excretion. Several studies have shown no association between water hardness and the incidence of urinary stone formation."

"Although, there is some evidence from epidemiological studies for a protective effect of magnesium or hardness on cardiovascular mortality, the evidence is being debated and does not prove causality."

Atopic dermatitis (or eczema) is an inflammatory, chronically relapsing, non-contagious and pruritic skin disorder. The environment plays an important part in the etiology of atopic eczema, but the specific causes are unknown. Exposure to hard water is thought to be a risk factor for eczema."

It is my professional experience that having some water hardness is good as long as the cations composing the hardness are not above a drinking water standard, the water is not creating nuisance, or the water is causing a premature failure of a heat exchange system or appliance or violates a manufacturers warranty. In general, individuals do not report aesthetic problems with their water until the hardness concentration typically exceeds 160 to 180 mg CaCO3/L. I am more concerned about water with very low hardness that may be associated with corrosion of fixtures and piping. If I had to have a preference, I would probably choose "moderately hard" water.

What are the Standards for Hardness?

There is no specific drinking water standard for water hardness, but the associated secondary drinking water standards may include the total dissolved solids of the water, potential for corrosion or scale formation, or the elevated presence of some iron and manganese and other similar metals. The classification of hardness:

Total Hardness Levels (mg CaCO3/L)
Soft 0 to 17.1
Slightly Hard > 17.1 to 60
Moderately Hard > 60 to 120
Hard >120 to 180
Very Hard > 180


(Source: Lehr, J. et. al., 1980. Domestic Water Treatment, New York, NY: McGraw-Hill Book Company - Note: This is a great desk reference if you can find it.)

Get Tested | Hardness

There are some warning signs of a problem with hardness and issues with hardness can occur when the hardness is too low or too high, but these issues can be controlled by changing both the cationic and the anionic concentrations in your water. Problems associated with hardness are not normally associated with an odor problem, but more typically an aesthetic problem, such as a coating, film, scale, hard water spots, and poor sudsing. Since hardness is a general term that covers a group of cations, it is normally necessary to conduct a comprehensive water test and not just test the hardness of the water. Your best course of action is to get your water tested and compile as much information as possible about your water supply source, well construction, surrounding land-use, and local geology.

Level 1 | Observational Self-Testing

Level 1 Testing is done with simple observations that an individual can make with their own senses such as sight, smell, and taste. These observations can be readily apparent or can be observed as they change over time. In addition, accessible related information about the home can also be used to narrow down the cause of your water issues.

Notes on Level 1 Testing for Hardness

Hard water interferes with almost every cleaning task from laundering and dish washing 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 deposits in pipes and aeration devices may have a chemical coating that appears white or gray.

Observations for Hardness

Water hardness problems can be an issue if the hardness is too low or high.  Very low hardness may be associated with chemical corrosion of the water and a metallic or acidic taste and elevated hardness can be associated with chemical coatings, films, coatings, clogged piping, and dingy clothing.

Level 1 | Self-Test Web App
To do a quick and easy self diagnosis of your water, click the button below.
Launch

Level 2 | Do-It-Yourself Testing

Level 2 Testing is Do-It-Yourself testing that can be done in your own home using a Testing Kit. After you’ve done Level 1 Testing, Level 2 Testing can confirm if your observations are correct. If your test results reveal the presence of a contaminant that is cause for concern, you can either proceed to determine the best treatment (see below) or continue to Level 3 Testing.

Notes on Level 2 Testing for Hardness

There are a number of low cost ways to measure the total hardness of your water at home. In most cases these at-home tests are very easy to use, but do not provide a very accurate or precise measure of the water hardness, but can provide a value to help you to determine if the water is soft, slightly hard, moderately hard, hard, or very hard.

Recommended Level 2 Tests
National Testing LabsWater Check Deluxe

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Level 3 | Informational Testing

Level 3 Testing is done through an accredited Water Testing Laboratory. With Level 3 Testing, you can order a testing kit that is used to prepare your sample and submit it to the lab. By utilizing a lab, you have the assurance that a certified water expert had analyzed your water sample. If your test results reveal the presence of a contaminant that is cause for concern, you can either proceed to determine the best treatment options (see below) or continue to Level 4 Testing - Certified Testing.

Notes on Level 3 Testing for Hardness

Most informational water tests provide testing for the total hardness and some test kits provide additional insight into the other cations and anions that are contained within the water. These comprehensive water testing kit results are needed to determine whether the water needs treatment and, if so, to help design the treatment system.

Recommended Level 3 Tests
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Level 4 | Certified Testing

A Level 4 Certified Test Test uses chain-of-custody with a water professional coming to your home to prepare the water sample and then works with an accredited laboratory in order to certify your test results. This type of testing not only gives you the highest level of assurance in the accuracy of your test results, but can also be used as a document in legal cases. For Baseline Testing, we recommend that you use Certified Testing.

Notes on Level 4 Testing for Hardness

If you require certified testing for total hardness or a hardness-related issue, we strongly recommend completing the diagnostic analysis to ensure that the water does not show signs of having a bacteria problem or a problem related to the presence of a specific cation like Aluminum, Iron, and Manganese or elevated anions like Chloride, carbonates, bicarbonate, or Sulfate. If you need assistance, please Contact our team.

Get Treatment | Hardness

In most cases pretreatment will not be necessary, but if you have a Bacterial problem or have high settleable solids or Turbidity, it may be necessary to install a whole-house pretreatment system that may include a disinfection system or a back washable/ disposable Particle Filter. The most common means to soften a water or to reduce the total hardness is the use of a water softener ion exchange system (using salt) or a non-precipitating water softener (no salt) that helps to sequester (bind the multivalent cations into complexes that keep them in solution) the multivalent cations. The "salt" based units will exchange sodium or potassium ions for the multivalent cations such as calcium and magnesium whereas, the "no salt or salt free" will typically sequester the multivalent cations by complexing them with additives such as NUVO (citric acid) and Aquios (polyphosphate). Another type of “no salt” system contains an active media, i.e., catalytic media, that removes the hardness cations by causing them to precipitate or crystalize. Typically, the NUVO and Aquios units are needed when we are only looking to slightly reduce the water hardness.

Short-Term Treatment

In the short term and assuming you do not have a problem with any trace metals, you can boil the water and then filter the water. The process of boiling will cause some of the carbonate to be converted to CO2 and the cations causing "temporary hardness" will form a precipitate that can be filtered from the water. You could also install a faucet-mounted or under-the-counter filtration system that contains a catalytic medium.  If you use one of the Aquios or Nuvo units, you may want to consider adding a point-of-use Reverse Osmosis unit.

Recommended Short-Term Treatments

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Contact a KnowYourH2O Recommended Professional

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Long-Term Treatment

In the long term, the choice of options depends on the situation and degree of your problem. If you are only looking to slightly reduce the hardness of the water and you have limited space, you may want to consider the NUVO or Aquios units which will require that you change one or more filter cartridges every 6 months. There are also no-salt systems that contain a catalytic medium which would have to be rebedded every 750,000 gallons or more depending on the degree of hardness. For very hard water, we suggest the standard "salt" based water softening systems. These systems will have an automatic backwash cycle and have a "salt" tank to create the brine that is used to regenerate the system. Do note, however, that such ion exchange systems add sodium to the water which could be a problem for people with high blood pressure.

Recommended Long-Term Treatments

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<div class="product-note in-L6-beta-particles">Note: If the beta  dosage equivalent is < 4 millirems/year and Radium 226 + Radium 228 is < 5 pCi/L - (POE Device)</div>
<div class="product-note in-L6-radium-226-and-radium-228">Note: If combined radium concentration is < 5 pCi/L and alpha, beta, uranium, and radon are low - (POE Device)</div>

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<div class="product-note in-L6-gross-alpha">Note: If the alpha concentration is < 5 pCi/L and Radium 226+ Radium 228 is < 5 pCi/L - (POU Device)</div>
<div class="product-note in-L6-beta-particles">Note: If the betadosage equivalent is < 4 millirems/year and Radium 226+ Radium 228 is < 5 pCi/L - (POU Device)</div>
<div class="product-note in-L6-radium-226-and-radium-228">Note: If combined radium concentration is < 5 pCi/L and alpha, beta, uranium, and radon are low - (POU Device)</div>
<div class="product-note in-L6-uranium">Note: Final Barrier After Treatment Implemented</div>

View
Contact a KnowYourH2O Recommended Professional

Not Up for A DIY or you have a series of issues: Need Help Identifying a Local Know Your H20 Team Professional? Contact Us

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