Does a Whole House Water Filter Remove Calcium?

Author: Rory Mullan - Published: 2022/02/04 - Updated: 2022/11/22

Disclaimer: This page may contain affiliate links. If you buy a product or service through an affiliate link, we may earn a commission but at no additional cost to you. You can view our full affiliate disclosure here.

Chances are, your water supply contains tons of impurities, including calcium.

The mineral generally leaches into water through groundwater and contributes to water hardness.

Savvy homeowners often install whole house water filters with the goal to remove calcium content. But does this even work? We’ll find out!

So, here is our guide answering the question, does a whole house water filter remove calcium?


  • Most whole house water filters are not particularly effective in removing calcium because they are not designed for that use.
  • A water softener is the preferred choice here.

Does a Whole House Water Filter Remove Calcium?

Do Whole House Water Filters Remove Calcium Thumbnail

Generally, whole house water filters use several filtration stages to remove harmful contaminants and solve underlying aesthetic water issues. Simply put, they trap unwanted pollutants and improve your water’s odor and taste.

However, standard whole house filtration systems are not built to target calcium in water.

A few with small micron ratings might trap large calcium particles, but that’s all there is to them.

Water softeners on the other hand actually work to eliminate calcium from water. But, water softeners are pretty different from water filters (more on this below).

What is the Source of Calcium in Water?

Calcium is found naturally in water.

It dissolves from rocks, including marble, limestone, fluorite, apatite, dolomite and gypsum, when the water moves through the ground.

Measuring Calcium Levels in Water

Water Hardness Defined

Before we discuss the procedure of measuring calcium in water, it’s essential to learn about water hardness because calcium essentially contributes to it.

Typically, water is referred to as soft, moderately hard, hard, very hard or extremely hard. The hardness level is determined by the presence of calcium carbonate. That is, the higher the amount of calcium present, the higher the water hardness level.

Generally, calcium levels are measured in mg/L (milligram per liter) ppm (parts per million) or gpg (grains per gallon). Industries measure calcium concentrations in gpg.

1 ppm equals 1 mg/L. When converting ppm or mg/L to gpg, you need to divide it by 17.12.

Testing for Calcium

There are several ways you can determine calcium levels in your water.

  1. Collect a water sample and send it to a laboratory. A lab specialist will measure the calcium concentration in your water and send you accurate reports. This is the costliest option.
  2. You can also measure calcium concentrations using DIY kits. They are readily available and won’t cost you much. This is our recommended way.
  3. Another way to learn about calcium levels in your water is by looking into to the Water Quality Report from your local water provider. However, these so-called Consumer Confidence Reports are only available for people on a municipal water supply.

Is Calcium in Water Troublesome?

Long story short, calcium in water does not pose a risk to your health.

But it still can be a huge problem! Here are a few ways calcium can be troublesome for you:

  • A high amount of calcium can cause skin dryness and hair tangles. Even worse, bathing regularly in hard water can lead to itchiness and dandruff.
  • If you use hard water to wash your clothes, towels and bed sheets, it can fade the color of the fabric over time. Also, the laundry will feel rough to the skin.
  • Hard water also contributes to nasty stains on all kinds of surfaces such as bathroom fixtures and shower doors. These stains occur because as the water evaporates, it leaves limescale behind.
  • Hard water also inactivates the active ingredients in synthetic cleansers. As such, the cleansers lose their effectiveness, meaning you have to use more to achieve the desired results.
  • Lastly but certainly not least, calcium-laden water can decrease water flow rates and lead to leakages throughout your entire home due to scale buildup. Pipes and home appliances are equally affected. As a result, you may need to spend money time and again on replacements.

Health Effects of Calcium

As mentioned earlier, calcium in water isn’t dangerous at all.

Quite the opposite, health professionals regard the mineral as beneficial. And on average, about 20 percent of our daily required calcium intake comes from the water we drink.

Research even indicates that calcium consumption increases bone mass growth[1] in osteoporotic patients and decreases bone loss and fractures.

Bottom line, you won’t experience health effects by drinking water containing regular to increased amounts of calcium.

However, it can lead to dry hair and skin when showering or bathing in it, which perhaps might be an issue for you.

How to Reduce Calcium in Your Home Water Supply?

If you’re high maintenance, calcium present in water might irritate you. It’s not easy to deal with tough stains everywhere around your house.

So, to avoid trouble, it might be better to remove it.

However, note that a standard water filter is not designed to target calcium.

But, water softeners can be used for that very purpose.

Water Softeners

water softeners

A water softener can significantly reduce the amount of calcium in your water. In fact, a water softener only works to remove hard water minerals, and that’s all. In comparison, a whole house filtration system eliminates all kinds of water contaminants, making your water clean and safe to use.

In a nutshell, water softeners replace calcium with sodium or potassium in a process called ion exchange. Exchanging ions is what makes water soft.

Here’s how a traditional ion-exchange water softener may help you.

  • A quality system will help you get rid of tough stains around your kitchen and bathroom, making house cleaning so much easier for you.
  • By preventing scale deposits, water softeners enhance the life of your home appliances like dishwashers, coffee makers, water heaters and washing machines. Costly maintenance and repairs can be avoided.
  • Low levels of calcium will prevent your clothes from fading.

RO Systems

Reverse osmosis systems can also be used to successfully eliminate hard water minerals just like most other water impurities. Simply put, an RO system provides almost pure, soft water.

If you’re dealing with hard water, RO filter systems should not be used in a whole house application without prior treatment though. This will only lead to rapid clogging of the filter elements, especially the reverse osmosis membranes.


Whole house water filters don’t remove calcium which occurs naturally in water.

Calcium in water causes hardness which is usually measured in parts per million or grains per gallon.

Fortunately, ingesting calcium through water isn’t harmful, but it can cause various issues in your home such as spotting/staining and limescale buildup in the plumbing system.

Water softeners and reverse osmosis systems can be used to lower calcium concentrations.

Further Reading


Meet Rory Mullan

Rory Mullan Rory has joined the Water Masterz team as a contributing writer. He has covered all sorts of topics in the last several years.

Outside of his writing work, Rory enjoys photographing the Irish landscape and making music!

Leave a Reply

Your email address will not be published. Required fields are marked *

12 + thirteen =