What is Hard Water?

Posted by
John Woodard on September 04, 2019

Over 85% of American households use hard water as their household water supply. Hard water is one of the most prevalent and frustrating water quality issues a homeowner can face. From destroyed plumping to higher energy bills to sticky skin and lifeless hair, hard water is a nightmare to live with. Join John Woodard, our Master Water Specialist, as he discusses what hard water is, what it does to your home, and how you can solve your hard water problems.

What is hard water? 

Hard water is water with an abundance of mineral content, specifically calcium and magnesium. This mineral-rich water causes devastating effects on household appliances. Water hardness minerals resist dissolution and seek to return to a hardened form. When hard water is heated, calcium ions form calcium carbonate, a precipitate formation also known as scale. Scale accumulates in pipes, clogging them and reducing water pressure. Scale also forms inside water heater appliances, shortening their lifespan and increasing energy bills. The minerals in hard water resist lathering with soap and leave behind unsightly white soap scum all over your bathroom and kitchen. In a home plagued by hard water, showerheads lose flow, laundry is dull and dingy, and dishes emerge from the dishwasher streaked and cloudy.

Classification PPM or mg/L Grains per gallon
Soft 0 - 17.1 0 - 1
Slightly hard 17.1 - 60 1 - 3.5
Moderately hard 60 - 120 3.5 - 7
Hard 120 - 180 7 - 10.5
Very hard 180+ 10.5+

What causes hard water? 

Hard water is caused by elevated levels of calcium and magnesium that water collects as it journeys from rain to underground aquifers. Hard water is a natural result of the hydrologic cycle. Water evaporates from our oceans, transforming into clouds and then precipitating back down to earth in forms like rain and snow. Water is known as a universal solvent, and when it hits the earth as precipitation it is soft and slightly acidic. Water then percolates through the soil and rock into underground aquifers, passing through layers of limestone and gypsum. These rocks are rich in calcium and magnesium, which the water readily absorbs as it filters through them. 

Is well water hard water? 

Well water is very likely to be hard water because of its reliance on groundwater supplies. Hard water is predominantly found in groundwater, which is used by both wells and municipalities alike. Surface water supplies like large lakes or reservoirs are fed primarily by precipitation and rain, so they avoid contact with heavy mineral content. Groundwater seeps through layers of mineral-rich rock on its path to underground aquifers, absorbing hardness-causing minerals like calcium and magnesium along the way. Well owners rely on groundwater for their home water supply, so though well water it isn’t inherently hard, its prolonged exposure to the earth means it probably has elevated hardness levels. However, many city suppliers use hard groundwater for municipal distribution as well, so the problem is far from limited to well owners or rural areas.

How do I know if I have hard water? 

If you live with hard water, odds are you are already aware of it. From rattling heaters to spotty glassware and dishes, it’s hard to miss the signs that you are living with hard water. However, if you are unsure, you can purchase total hardness test strips that will determine your water’s hardness levels. You can also purchase a liquid hardness test kit, which provides you with results based on a color-changing solution. 

If you want to test your water hardness at home without a kit:

    1. Fill an empty water bottle halfway up with tap water. 
    2. Add in ten drops of dish soap. Make sure the soap is free of perfumes, dyes, and detergents, as these can affect results.  
    3. Screw the cap on and vigorously shake the bottle. 
    4. Observe. If the bottle is filled with sparkling bubbles and suds and the water is clear, you have soft water. If barely any lather has formed and the water is a milky, cloudy color, you have hard water. 
    5. Continue to add soap bubbles. The more soap required to make the water lather and fill with suds, the harder that water is. 

This DIY test is a good indicator of whether or not water hardness is a problem for your home, but it will not provide you with results as accurate as an actual water hardness test. 

hard water showerhead

The hard cost of hard water 

The cost of living with hard water damage is staggering. If you live in hard water country, an estimated 20 cents out of every dollar you spend at the grocery store will go toward cleaning supplies to combat the damages of hard water. This includes laundry detergent, shampoos, conditioners, dish soap, bleach, and dishwasher detergent, to name a few. This doesn’t take into account the enormous costs of repairing appliances like water heaters and replacing corroded and scale-covered piping in your home. Hard water is drain not only of money but of time and energy poured into the excessive cleaning and maintenance of your home.

Hard water and laundry

Clothes washed in hard water are stiff and scratchy. Hard water fades clothing, turning brightly-colored clothing dingy and drab. Denim becomes brittle and uncomfortable, and towels lose their plush softness. Hard water furthermore destroys the laundry machine itself, as the washer’s water heating element will quickly become destroyed by scale. Laundry washed in hard water also demands more detergent to remove stains, demanding more than double the standard detergent to achieve a normal wash. The Battelle Institute’s study on hard water found soft water was better at removing stains on white clothing at low temperatures with less detergent than hard water at a higher temperature and twice the detergent. 

Hard water and hot water appliances 

Scale formed by hard water is a detriment to hot water appliances. When an electric water heater accumulates scale, the appliance has to heat the scale caked on the heating element before it can heat up the water. A gas-fired heater encounters the same problem, heating up the accumulated scale at the bottom before it can heat any water. This leads to exorbitant energy bills. It also rapidly shortens hot water’s appliances lifespans. Hard water causes tankless water heaters to completely fail after only a year and a half. Gas-heaters lose as much as 25% of their efficiency on hard water. Electric water heaters gain half a pound of scale a year for every 5 grains of hardness in the water. 

Hard water and hair & skin 

Soap struggles to lather properly when faced with hard water. The minerals in hard water render the cleaning properties of soap ineffective, requiring you to use more of it to bathe. After emerging from the shower, the soap will stick to your skin in a filmy residue. The minerals in hard water create a film on your hair, preventing it from properly moisturizing. This leaves hair tangly, dry, and lifeless. Your showerhead will also fall victim to hard water scale. This lowers pressure and can cause a new showerhead to lose 75% of its flow rate in just a year and a half. 

Hard water and soap scum

The white soap scum streaking your shower walls and bathtubs is another nasty byproduct of hard water. When hard water comes into contact with soap, it forms a precipitate sticky soap curd. This soap scum is a result of the calcium and magnesium bonding with the sodium in the soap and forming an insoluble substance called calcium or magnesium stearate. If left alone, soap scum will continue to proliferate and harden and can grow mold and mildew. Soap scum can leave watermarks and is difficult to clean. It can be scrubbed away with Borox or white vinegar, but until the hard water problem is addressed, soap scum will continue to tarnish your bathroom surfaces.   

Is hard water bad for you? 

Hard water is safe to drink and presents no serious health risks. The heightened levels of mineral content in hard water are not a health concern as much as a danger to your home and property. However, the human body receives the majority of its healthy minerals from consuming fruits and vegetables. There is no reason to rely on hard water for your daily supply of magnesium and calcium, and water is not the ideal method for mineral consumption. Though it is not dangerous to consume, any perceived health benefits from drinking hard water are marginal at best and debated by the medical community. 

hard water damage

The solution to hard water

To treat hard water you’ll need to invest in a whole-house water filtration system. This ensures that the entirety of your home and appliances are protected from the corrosive effects of hard water. There are two popular solutions to combating hard water. 

Anti-scale systems

Anti-scale systems, sometimes referred to as salt-free water conditioners or descalers, use template assisted crystallization (TAC) to crystallize the hardness minerals and render them unable to form scale. Anti-scale systems do not actually soften the water. They are water conditioners. The water is still as hard as it was before the crystallization process, the minerals are just unable to adhere to surfaces. Anti-scale systems are adept at preventing scale from clogging your home’s faucets and pipes (the hardness crystals can actually clear out the preexisting scale from pipes.) Ultimately, you will not see the same extensive improvements that you would see from a water softening system. Water conditioners will not brighten laundry, improve soap’s lather, or prevent your dishes from looking cloudy and unwashed.  

| Learn more about the myth of "salt-free water softeners". |

Water softeners

A water softener removes hardness-causing calcium and magnesium from the water through a process called ion exchange. Resin beads imbued with sodium ions strip the water of minerals as it passes through a tank and into your house. During the ion exchange process, the magnesium and calcium ions are exchanged with sodium ions. The softened water then flows into your house, free of scale-causing hardness. Water softeners have come under scrutiny for adding sodium to the water, but water softening is by far the most effective way to eliminate water hardness and it’s respective consequences. 

| Learn more about how water softeners work. | Explore 5 benefits of having a water softener. |

How much sodium is in softened water? 

The amount of sodium added by water softeners is directly correlated with the hardness of the water it is treating. For every grain of hardness in the water, 30 milligrams of sodium is added. So, if you have very hard water, say 15 grains per gallon, you would have 450 milligrams of sodium per gallon (15 grains per gallon x 30mg of sodium per gallon = 450 mg). There are sixteen cups in every gallon, so, dividing the 450mg by 16 cups gives you 28.12 mg of sodium per 8 oz glass of water. This is a relatively insignificant amount of sodium in comparison to the majority of foods and beverages. 

For contrast: 

Food & Beverage Milligrams of Sodium
1 glass of softened water (8 oz) 28.12mg
1 glass of nonfat milk (8 oz) 120mg
1 slice of white bread 170mg
1 slice of cheese pizza 565mg
1 tablespoon of soy sauce 880mg

Softened water will not add considerable amounts of sodium to your diet. Unless your doctor has advised you to limit sodium intake for health reasons, there is little cause for concern. 

How do I remove the sodium from softened water?

The most effective method of removing sodium from your softened water is a reverse osmosis system. Reverse osmosis forces water through a semi-permeable membrane capable of eliminating dissolved salts and solids from your water supply. Unlike water softeners and anti-scale filters, reverse osmosis systems are point-of-use filtration systems. They can fit beneath your kitchen sink and provide you with sodium-free water to drink, cook, and make ice. If you are interested in restricting your sodium consumption but live with hard water, an RO system will strip all the sodium added by the softener’s ion exchange process as well as any naturally occurring sodium in the process.

| Learn more about how reverse osmosis works. |  

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