Hard Water vs. Soft Water: Which One is Better?

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By Eric Phillips


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Soft water is undoubtedly better. With its ability to extend the lifespan of home plumbing and appliances, deliver vibrant and cleaner laundry, enhance cleaning efficiency, improve skin and hair, and save you hours of frustration, soft water offers undeniable advantages, translating to an estimated annual savings of $2,916.

The main difference between hard water and soft water lies in their calcium carbonate (CaCO₃) concentrations. Hard water typically contains 120 milligrams per liter (mg/L) or 120 parts per million (ppm) or 7.01 grains per gallon (gpg) or more of calcium carbonate, whereas soft water has 60 mg/L (60 ppm) or 3.51 gpg or less of calcium carbonate.

Check out the table for a side-by-side comparison of the unique properties of hard and soft water.

CharacteristicsHard WaterSoft Water
Calcium Carbonate ConcentrationTypically contains 120 mg/L (120 ppm or 7.01 gpg) or moreTypically contains 60 mg/L (60 ppm or 3.51 gpg) or less
Plumbing and FixturesMineral deposits can clog pipes and reduce water flow, while fixtures may experience unsightly chalky white or greenish-yellow residue that interrupts the water flowNo mineral buildups in pipes and fixtures, and no effect on water pressure
AppliancesScales build reduce efficiency and prone to break down earlier than expectedNo scale formation, thus extending the life of appliances and improving their efficiency
LaundryAppear dull, faded, or stiff due to mineral buildup in fabricsFabrics remain softer and brighter
Skin and HairCauses dryness and roughnessLeaves skin and hair smooth and moisturized
Health ConcernsNo significant health risksNo significant health risks
Dishes, Glassware, and SilverwareLeaves spots, streaks, and a soapy residue on dishes, glassware, and silverware after washingDishes, glassware, and silverware appear cleaner and spot-free
Lather FormationDifficult to form lather with soap, cleaning solutions and other detergentsLathers easily with soap, cleaning solutions and other detergents
Cleaning EfficiencyReduces the efficiency of cleaning agents and requires more soapEnhances the efficiency of cleaning agents and uses less soap
Time and MoneyCostly and time-consuming plumbing and appliance repairs or replacements can add an estimated $2900+ annuallyNo serious plumbing or appliances repairs due to water. Saves you $2900+ annually
Comparison table: Hard Water vs. Soft Water

What is Hard Water?

Hard water is water with a high concentration of dissolved calcium, and magnesium minerals. It often includes metallic elements such as iron, manganese, aluminum, lead, copper, barium, strontium and zinc. This mineral-heavy water causes detrimental effects on plumbing systems and household appliances.

When hard water is heated, the calcium (Ca2+) and magnesium (Mg2+) ions in the water react with bicarbonates (HCO₃-) to form calcium carbonate (CaCO₃) and magnesium hydroxide (Mg(OH)2). These minerals precipitate out of the solution and form hard, white deposits known as scales or limescale.

Scale build-ups clog pipes, reduce water pressure, and pose risks of plumbing damage. Scale deposits in water heaters and dishwashers decrease efficiency and increase the likelihood of malfunction. Minerals in hard water resist lathering, resulting in unsightly white soap scum all over the bathroom and kitchen. Plus, these minerals hinder thorough rinsing, leading to dryness and itching on skin and hair.

Furthermore, hard water causes laundry to feel stiff and soapy even after rinsing, while dishes emerge streaked and cloudy.

Water hardness is measured in milligrams per liter (mg/L) or grains per gallon (gpg) of calcium carbonate equivalent. The United States Geological Survey (USGS) classifies water hardness standards as follows:

Classificationmg/L or ppmGrains per gallon (gpg)
Soft water0 – 600 – 3.51
Moderately hard water60.1 – 1203.51 – 7.01
Hard water120.1 – 1807.01 – 10.52
Very hard water180+10.52+
Table classifying soft water and hard water based on milligrams per liter and grains per gallon units.

What Causes the Hard Water?

Hard water is caused by elevated levels of calcium and magnesium ions in the water as it picks them up from rocks and soils during its journey from clouds to underground aquifers. These minerals are introduced through the natural hydrologic cycle, also known as the water cycle.

The hydrologic cycle begins with evaporation from oceans, seas, lakes, and rivers, transforming water into vapor without significant minerals. The vapor then cools and condenses into mineral-free cloud droplets, leading to precipitation as rain, snow, sleet, or hail with low mineral content. As water falls back to the earth, it percolates through the soil and rocks towards underground aquifers. During this journey, water, as a universal solvent, absorbs hardness-causing minerals like calcium and magnesium found in limestone, gypsum, dolomite, and other rock or geological formations.

Is Well Water Hard Water?

Yes, well water is hard water because it mainly comes from groundwater stored in aquifers. Groundwater percolates through layers of mineral-rich rock formations on its path to underground aquifers and naturally picks up hardness-causing minerals like calcium and magnesium. This leads to an increase in its hardness levels.

Well-owners typically use groundwater for their home water supply. Although the well water isn't inherently hard, its prolonged exposure to the ground makes it hard due to the dissolution of hardness minerals.

What are the Signs of Hard Water?

More than 85% of American homes have hard water, as reported by the USGS. With such prevalence, it's highly likely you may already be familiar with hard water. Common signs of hard water include:

  • White, chalky residues and greenish-yellowish slime on sinks, showerheads, and shower walls in your home.
  • Washed clothes appear dull, faded, and not as clean or bright as expected.
  • Stains or discoloration on sinks, bathtubs, and toilets.
  • Faded or discolored tiles and grout in bathrooms and kitchens.
  • Water has an unusual smell and taste.
  • Appliances lose efficiency and break unusually fast.
  • Scales buildup inside tea kettles and coffee pots.
  • Soap scum on hands, shower walls, and doors.
  • Visible water spots and streaks on glass surfaces, mirrors, and windows.
  • Residue left behind on dishes, glassware, and cutlery after washing.
  • Getting a good lather from soap, shampoo, and detergents becomes challenging.
  • Requiring increased amounts of cleaning solution to achieve the same level of cleanliness.
  • Reduced water flow from faucets, showerheads, and sinks.
  • Dry and rough hair and skin.

However, if you're still unsure, try total hardness test strips or liquid hardness test kits to get a basic idea of your water's hardness level. For accurate results, get your water tested for dissolved solids by a certified laboratory.

Which Regions Have Hard and Soft Water in the U.S.?

The regions with the hardest water in the United States are the Midwest, Arizona, Utah, western Texas, and Florida, where the water hardness measures 180+ mg/L (180+ ppm) or 10.52+ gpg. Moderately hard water is prevalent in the Northeast, Southeast (excluding Florida), and Southwest, with a range of approximately 120 to 180 mg/L (120 to 180 ppm) or 7.0 – 10.52 gpg. On the other hand, the softest water in the United States is found in the Northwest and the Mid-Atlantic, boasting a water hardness of 0 to 60 mg/L (0 – 60 ppm) or 0 to 3.51 gpg.

Map of Water Hardness in the United States
Map showing water hardness levels across the U.S. (in mg/L)

The water hardness information in regions across the U.S. is based on data collected by the USGS's National Water Quality Network (NWQN) back in approximately 1975. Since water hardness is mainly determined by geology, it has remained relatively unchanged over the course of 40+ years.

What are the Disadvantages of Hard Water?

There are six major disadvantages of hard water:

  • Plumbing damage: Hard water wreaks havoc on home plumbing. When hard water with minerals flows through pipes, scale deposits cling to the insides of pipes, causing serious clogs and reduced water flow, affecting the water pressure in your entire home. Those clogs put a strain on your plumbing, leading to leaks and bursts, leaving you with a hefty repair bill and a lot of wasted time. Moreover, those unsightly white, chalky scales also find their way into the tiny holes of your faucets and showerheads, causing them to drip and spray unevenly.
  • Appliance inefficiency and malfunctioning: Scale is a prime enemy of appliances like hot water heaters, dishwashers, coffee machines, and kettles. It coats their heating elements and internal components, greatly reducing efficiency and causing malfunctions that shorten their lifespans. As a result, you end up facing costly repair bills and often the need for replacement of these appliances. In coffee makers, scales obstruct water flow and the heating process, resulting in longer brewing times, inconsistent water temperature, and even flakes floating in your coffee or tea. Furthermore, hard water clogs nozzles and filters that produce uneven extraction and a ruinous effect on your coffee, espresso, and fountain beverages.
  • Soap scum and lathering issues: Calcium and magnesium ions in hard water react with soap's fatty acids, forming a sticky, white, or gray residue known as soap scum. This thick scum clings to the walls of showers, bathtubs, sinks, faucets, tiles, and dishes, making them look dull and time-consuming to clean. Moreover, hard water prevents soap from lathering properly, leading to small, weak bubbles that disappear quickly. This necessitates more soap for desired lather and cleaning, resulting in costs stacking up over time, if left unattended.
  • Dry and itchy skin and hair: Minerals in hard water create a film on the skin, preventing moisture absorption that results in dehydrated skin. The film also disrupts the natural oils, leaving the skin vulnerable to dryness and irritation. Similarly, on the hair, this filmy layer causes it to appear dull, lifeless, and weighed down, while also clogging hair follicles and leading to issues like dry, rough, and tangly, along with problems like dandruff and itchy scalp.
  • Dingy and faded laundry: Due to hard water, soap scum forms on laundry fibers, preventing the detergent from fully penetrating. As a result, clothes retain dirt, oil, and stains even after washing, giving them a dingy and discolored look. White clothes turn grayish and lose their brightness, while elastic ones lose their stretchiness. Hard water requires 15% to 30% more detergent than the standard amount for a normal wash, states the University of Wyoming. Moreover, hard water can also be detrimental to the laundry machine itself, as the formation of scales on the heating element hinders its efficiency and leads to premature destruction.
  • Stained glassware and dishes: Hard water leaves cloudy appearances on glassware and dishes as soon as they dry, giving them a dull and dirty look even after washing. These spots can be particularly frustrating for drinking and wine glasses, as they negatively impact the overall presentation and appearance of a table setting. Additionally, dishes washed in hard water appear foggy, and soap spots can streak the rinse, making them look unclean and detract from the enjoyment of a meal.

Is Hard Water Bad for Your Health?

No, hard water isn't a health risk. There is no clear evidence that hard water has any significant health effects, according to the World Health Organization (WHO).

A 2018 study titled “Hardness in Drinking-Water, its Sources, its Effects on Humans and its Household Treatment” found no adverse effects associated with drinking hard water. In fact, due to its abundance of calcium and magnesium, hard water can help strengthen bones and teeth.

Concerns may arise about consuming too much magnesium from hard water, as high quantities of magnesium can have a laxative effect, meaning it causes some people to experience more frequent bowel movements. However, McGill Office for Science and Society dismisses this concern as highly unlikely. On average, consuming two liters (0.52 US gallons or 8.5 cups) of hard water a day would only provide around 52 mg of magnesium, which is well below the recommended daily allowance (RDA) of over 400 mg by Harvard T.H. Chan School of Public Health. So, the amount of magnesium in hard water isn't likely to cause any issues with digestion.

Another study from the International Journal of Preventive Medicine in 2013, titled “Potential Health Impacts of Hard Water,” suggested that the calcium and magnesium present in hard water may act as protective factors against cardiovascular diseases.

What is Water Softening?

Water softening is a popular method to remove hardness minerals like calcium and magnesium from water through an ion-exchange water softener. The system uses spherical, polystyrene-type gel resin beads coated with positively charged sodium ions to capture calcium (Ca2+) and magnesium (Mg2+) ions from the water and replace them with sodium (Na+) ions, resulting in softened water, free of scale-causing hardness.

Water softeners that utilize ion-exchange require minimal operational costs. For an average family of four, a standard efficiency softener typically takes 40 lbs of sodium salt, costing $10 to $25 per month that needs to be replenished every 6-8 weeks. The resin usually needs changing every 10 years. On average, ion-exchange softeners typically last 10 to 15 years, if properly backwashed. While whole-house water softeners initially cost $600 to $1,500, considering the daily expenses and frustrations caused by hard water, they are incredibly affordable.

Alternatively, there are water softeners that require no salt, known as water descalers or salt-free water conditioners. These systems use template-assisted crystallization (TAC) to convert hardness minerals into crystals to prevent scales and eliminating existing scale in plumbing pipes. They are relatively affordable, costing $180 to $400 on average and require no maintenance. However, it's important to note that since they alter the chemical makeup of calcium and magnesium instead of removing them, you won't experience the same benefits of softened water, such as vibrant laundry and spotless dishes.

Is Softened Water Bad for You?

No, softened water isn't bad for you unless you are on a strict no-sodium diet. For those on a low-sodium diet, it won't add significant sodium to your daily intake so it's unlikely to be a cause for concern unless your health expert advises limiting sodium.

Let's break down the numbers:

If your water has 20 grains per gallon (gpg) hardness (285.075 mg/L or 285.075 ppm), you'd get 600 milligrams of sodium per gallon (16 cups) since each grain adds 30 milligrams of sodium, according to the Water Quality Association (WQA). That's only 37.5 mg of sodium per 8 oz glass (600 mg divided by 16 glasses), which is relatively insignificant.

To put it into perspective, the sodium content in the majority of the food and beverages we consume daily is much higher. For instance, a glass of non-fat milk contains 129.85 mg of sodium, a single slice of whole wheat bread provides 147.56 mg of sodium, and a 140g slice of store-bought frozen pizza gives you around 765 mg of sodium on average.

On the bright side, there's no need to worry about removing calcium and magnesium minerals from hard water since we mostly obtain them from our regular diet. The trace amount of these minerals in water is insignificant compared to the time and money spent on combating hard water problems.

What is Soft Water?

Soft water is water that contains a low concentration of dissolved minerals, primarily calcium and magnesium ions, measuring less than 60 mg/L (60 ppm) or 3.51 grain per gallon (gpg). Additionally, it lacks significant amounts of dissolved metals such as iron, manganese, aluminum, arsenic, lead, copper, and zinc.

What are the Signs of Soft Water?

Common signs of soft water include:

  • You won't see white, chalky and greenish-yellowish deposits on plumbing fixtures like faucets and showerheads.
  • No more clogged pipes means water flows effortlessly from your faucets and showerheads.
  • Soap and shampoo lather easily, and a small amount creates rich suds.
  • Water-using appliances like water heaters, coffee makers, dishwashers, and washing machines, remain in tip-top shape, saving you from frustrating breakdowns.
  • Surfaces like countertops, sinks, and bathroom tiles are easier to clean and require less elbow grease.
  • Laundry stays soft, fresh and brighter.
  • With enhanced cleaning efficiency, you use less soap, shampoo, detergents, and cleaning products.
  • Smoother, moisturized skin and hair shines like silk.
  • Crystal-clear appearances of glass surfaces, with no more water spots on your shower doors and windows


In the end, soft water is the preferred choice, offering numerous advantages for your home plumbing, appliances, and overall well-being.

A water softening system prevents mineral deposits, extending the life of your plumbing systems, and enhancing the efficiency of cleaning agents. You'll save on repairs and replacements, leading to substantial savings over time. Soft water also benefits your skin, hair, laundry, and dishes, making it a worthwhile investment. Say goodbye to the frustrations of dealing with hard water by switching to soft water for your home.

Eric Phillips

Meet Eric, the Water Treatment Specialist and founder of Dripfina, where he shares his wealth of expertise. With notable features in Realtor, ApartmentTherapy, FamilyHandyMan, and more, Eric is a renowned expert in water treatment industry. Join Eric on Dripfina and benefit from #AskDripfina community to make informed decisions for clean, refreshing water.

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