Will A 5 Micron Water Filter Remove Calcium?

Calcium is an essential mineral that we need to live. While it’s all well and good to get it from sources like dairy and cheese, calcium in your home’s tap water can leave damaging deposits on your home’s surfaces.

These spots are called limescale and can be a huge hassle to get rid of. 

In this brief guide, we’re going to share a bit about water filtering devices and systems for removing calcium, including whether a Micron 5 filter will remove calcium from your water. 

Read on for more information. 

The Short Answer

Certain filters, such as ultrafiltration membranes and reverse osmosis devices, are able to reduce the calcium content in your water.

However, if the tap in your home water contains large volumes of the mineral, a water softener would be your best bet at getting rid of it, rather than a filtration system. 

The average water filtration device makes use of several filter stages to remove contaminants from your drinking water – contaminants like heavy metals, chlorine, harmful substances, and damaging organic compounds. 

Most house water filters are not made to filter calcium from water, though there are filters that have a small enough micron rating to be able to remove large calcium flakes.

These can help reduce the presence of the mineral in your water, though they may not be able to eliminate it entirely. 

Plumber installs or changes 5 micron water filter

Filters That Can Remove Calcium

If there’s one thing that you take away from this guide, let it be this: calcium water filters do not exist.

There is not a filter that is designed specifically to remove calcium from your drinking water because most of the technology is simply incapable of removing it. 

In fact, the best filters for removing calcium are not even designed for calcium filtration, but rather do so as an added benefit. These filters are ultrafiltration and reverse osmosis systems, and we’ll take a closer look at them now. 


Similar to reverse osmosis systems, ultrafiltration is a process of membrane filtration that makes use of a hollow fibre membrane to catch and remove contaminants that are as tiny as 0.01 microns.

These membranes are not quite able to remove contaminants that are as small as RO filters, but they can still remove calcium from hard water. 

In fact, ultrafiltration systems are capable of removing just over half of the calcium found in your drinking water.

We cannot guarantee that one of these systems will filter out calcium from tap water, though – some ultrafiltration devices are said to remove calcium, while others are not able to do so. 

Reverse Osmosis

Reverse osmosis filters contain semi-permeable membranes that are made up of tiny pores. These pores work to trap most of the contaminants found in your drinking water, and that includes both magnesium and calcium. 

Calcium particles are too big to pass through these reverse osmosis membranes and are instead pushed toward the reverse osmosis chamber. Here, calcium, as well as other contaminants, is flushed down a drain with a small volume of wastewater. 

Reverse osmosis systems are able to remove nearly 98% of magnesium and calcium carbonate from your home’s tap water, making them one of the most effective solutions for calcium filtration. 

The Most Effective Calcium Removal Solutions

While ultrafiltration and reverse osmosis systems certainly are able to filter calcium from your water, they are not the most optimal solutions. These are:

Water conditioner

If you don’t want to have to add salt to your water but still want to reduce the hardness of your water, then a water conditioner may be the best choice for you. 

Salt-free conditioners are highly effective at treating calcium contamination in your drinking water. These systems make use of a crystallisation process, preventing hard materials from getting stuck to your home’s surfaces and developing scale. 

One of the main differences between a water conditioner and a water softener (which we’ll discuss in a moment) is that these water conditioners actually do not remove calcium from the water.

So, the quality of your water will not change and you will still have calcium in your tap water. 

However, the magnesium and calcium ions in the water will no longer be able to develop scale deposits. 

Water Softener

Water softeners are, by far, the best way to remove calcium from your water. 

As the name suggests, they are designed for the sole purpose of softening hard water. Water softeners remove calcium via ion exchange, replacing magnesium and calcium with minerals that cannot cause scale, such as potassium or sodium ions. 

These systems are installed at the point of entry of your home, allowing the softener to treat your water before it moves through your pipes and into your home’s heaters.

This allows you to enjoy both hot and cold soft water throughout your home. 

Not only do water softeners reduce the concentration of calcium in your water, but they also eliminate water hardness entirely, preventing the formation of limescale for years to come. 

Why Is Calcium Bad For Water?

While calcium water is certainly safe and drinkable, high concentrations of calcium can cause limescale to form on your appliances and pipes. 

Calcium is a hard water compound, and it leaves gross, sticky deposits around your taps, in your plumbing, on showerheads, in your toilet, and in your washing appliances.

Limescale can be extremely damaging to these appliances, reducing their effectiveness. 

Do Water Filters Remove Hard Water Minerals?

Sadly, most water filters, like KDF and activated carbon filters, are simply incapable of removing minerals from hard water.

There really is no such thing as a calcium filter for hard water – certain filters, like reverse osmosis devices, have pores that are small enough to reduce hardness, although high hardness may cause damage to the reverse osmosis membrane. 

A filtration system of 5 microns will remove most particles that are visible to the naked eye. 1-micron filters will remove particles that are too small to be seen without a microscope, and 0.5-micron filters will remove almost all contaminants in your water. 

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