What Is the Ideal Water Hardness for Drinking? (& What’s Too Hard)

Hard water is a pressing issue for many homeowners. It causes annoying build up on surfaces and extends daily cleaning tasks. When it comes to hard water in a home, the taste of drinking water is a common concern. 

Water filters are necessary to purify drinking water, but they don’t get rid of the excess minerals found in hard water. Therefore, it’s essential to understand the levels in your home’s water source. With that said, what is the best water hardness for drinking? 

The ideal water hardness for drinking is between 60 and 120 mg/L (milligrams per liter). This is the perfect ratio for optimal taste and nutritional value. A level of 170 mg/L is considered too hard, and can be unsafe when consumed. The best hardness level for drinking water will depend on your individual taste preferences. 

In the United States, 85 percent of households have hard water. If you fall into this demographic, managing the hardness levels of your water source is essential. Keep reading to learn exactly how much water hardness is acceptable for drinking. 

What causes water to be hard?

Hard water is caused by high mineral content, specifically calcium and magnesium. 


Calcium is a mineral that naturally occurs in places where groundwater is sourced from, such as rivers and streams. It’s present in limestone, gypsum, calcite, and dolomite. 

When water travels through the ground, it collects minerals, including calcium, from the rocks it comes in contact with. As a result, the water contains calcium traces. In this natural state, the water is considered to be “hard.” 

Hard water with excessive calcium levels makes itself known in your home in a few ways. Showers and sinks are problem areas, as calcium mixes with soap to form scum. This can stick to surfaces, creating solid masses that are ugly and hard to clean. 

In addition to the water you shower, wash your hands, and clean with, the same calcium content affects your drinking water. Although not harmful to consume, the minerals alter the taste of water at noticeable levels. 


Magnesium is another mineral naturally found in various water sources. These include rivers and streams, as well as the ocean. In fact, magnesium makes up most of the ocean, after sodium. 

The mineral is derived from sedimentary rocks. Similar to calcium, when the water comes in contact with these rocks, the minerals are shed, resulting in magnesium content in water. 

Magnesium also contributes to water hardness, leaving behind stubborn residue in showers and sinks, and altering the taste of drinking water. 

Ideal water hardness for drinking water

Although the minerals in hard water alter the taste of drinking water, they are not necessarily unsafe to consume in specified quantities. Water hardness is measured in mg/L (milligrams per liter). 

In this section, you will learn how much hardness is acceptable for taste and safety. 

Acceptable levels for best-tasting water

Many people believe soft water tastes better than hard water because all of the excess minerals are removed. However, this is not necessarily the case. 

Calcium, magnesium, and other minerals that naturally occur in water contribute to the taste. This is why you will notice many products labeled as “mineral water” in the store that some people prefer to purchase at a premium. 

When drinking hard water, there are certain levels that are acceptable for the best taste. If the hardness levels are too high, the water can taste bad. On the other hand, a low mineral content moves further away from the taste many people prefer. 

As a general rule of thumb, the best tasting water falls between 60 and 120 mg/L. Anything more or less than this optimal range will alter the taste to unpleasant levels. 

What levels are safe for your health?

Certain water hardness levels can be beneficial or detrimental to your health. Water that’s too hard can give you a mineral overdose, while soft water is missing essential nutrients that people need to thrive. 

Water Hardness and pH

Soft water is treated using salt, which adds to the sodium levels of water for washing and drinking. Those with hypertension or high blood pressure concerns, for instance, should not drink soft water because of the high sodium. 

When it comes to safely drinking water in your home, you should ensure the hardness levels are no more than 170 mg/L. 

Water hardness tests

You may wonder how you can determine the hardness level of the water in your home without being able to see it. Fortunately, water hardness is measurable, and you can easily find out where your water falls on the spectrum by using the following methods. 

Soap test

It’s a known fact that hard water affects soap lathering in the shower and at the sink. The calcium content in the water reacts with the soap and leaves residue behind on your hands, hair, and body. 

Soap test

This knowledge can be used to test your water for hardness. Fill a clear, empty bottle full of water from your sink or shower at the ⅓ mark. Add in a few drops of clear soap and shake the bottle. 

The results of the test will show in the appearance of the water. If it’s extremely bubbly and fluffy, you have soft water. Cloudy water that’s not bubbly will indicate hard water. 

Home water hardness kits

Once you’ve determined your water is hard, you may seek a testing method with quantitative results. While the soap and water test will let you know if you have excess minerals in your water source, it won’t give you a number. 

Home water hardness kits are available at many online retailers and stores. They can be purchased for $10-20, and are easy to use. The kits are equipped with everything you need for results, including paper test strips and a color chart. 

Home water hardness kits

To perform the test, fill a bowl with water from the faucet and insert the strip. The instructions on the box will provide a comparison that will let you know how hard your water is. Alternatively, you can purchase a digital test that displays hardness levels when inserted into a bowl of water. 

Professional testing

After attempting DIY water testing methods, it never hurts to get a second option from a professional. If you’re dealing with troubling issues stemming from hard water in your home, you may require additional confirmation. 

Professional testing

Professional testing is typically done in a laboratory. You can find a testing site near you with a Google search and schedule a consultation to have your home’s water evaluated. 

While a professional test will be more time consuming and cost more, you can expect the most accurate results out of all of these options. However, if budget is more of a factor than accuracy, doing a DIY test may be sufficient. 

Treatments for hard water

So, what can you do about hard water in your home once you discover it? Knowing you have hard water in your home can be troubling, but there are steps you can take to treat it to acceptable levels. 

Water softener

A water softener is the best way to treat hard water in your home. After installation, all excess minerals will be removed from your water source, providing tons of benefits on the inside and out. 

Water softener

With soft water, you can say goodbye to cloudy buildup on shower glass and fixtures. When you wash your hands or bathe, soap will lather on smoothly without leaving sticky residue behind. 

Installation costs

When it comes to your water softener installation, there are two options: hire a professional or do it yourself. 

The national average cost of a professional installation, including labor and equipment, is $1,500. This can be as high as $5,000-$6,000 depending on the model and brand you choose. 

If you have some technical skill and decide to go the DIY approach, you will only need to pay for the unit itself. This can cost $100-$200. However, you should keep in mind that any installation mistakes can translate to higher repair costs, so make sure you know what you’re doing if you choose this route. 

In addition to just the cost of the unit and installation, you will need to keep monthly maintenance costs in mind. Water softeners use salt to extract minerals, which will become a monthly expense as refills are necessary. You can expect to pay between $10 and $20 per month to keep your unit up and running. 

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