Do Hard Water Shower Filters Work?I Asked The Manufacturers

I am stunned by the fact that there are so many articles online trying to make money by promoting ‘hard water shower filters’ or ‘hard water showerhead softeners’. This is because I spent a week poring through scientific articles and talking to shower filter manufacturers. And now, if you were to ask me- do hard water shower filters work? 

My answer would be that 99.99% shower filters do NOT work for hard water. They do not remove hard water salts from water OR soften water. I only found one exception that seems to work, which I’ll talk about towards the end of this post.

From small time affiliate website like Watersoftenercritic to even huge websites like Bustle, every one of them has at least one misleading article published online about ‘hard water’ shower filters.

Frankly I, like you and everyone else, believed that shower filters work for hard water until I did a little digging and found out how they work.

I contacted multiple shower filter manufacturers like Aquasana, Culligan, and Aquabliss.

I also researched popular shower filter technologies- KDF, Vitamin C, Activated Carbon.

Here’s one of the most popular websites, Bustle, recommending the Aquasana shower filter for hard water.

Bustle Article recommending aquasana as a hard water shower filter
Article on Bustle recommending Aquasana as a hard water shower filter

Now, let’s take a look at what the Aquasana representative I talked to said:

Email reply From Aquasana Rep stating that Aquasana Filters Do Not Remove Hard Water


Who would you rather trust? A few websites on the internet or the product manufacturer?

To stop all arguments, the following few sections are devoted to a breakdown of how each major shower filter technology works, and why it cannot act as a hard water filter.

If you’re already convinced, you may want to skip to the last section where I discuss REAL solutions to hard water softening/ filtration.

Here’s what I found out:

Do KDF Filters Soften Hard Water?

KDF(Kinetic Degradation Fluxion) technology works on the principle of redox reactions- it basically converts harmful contaminants in water to harmless substances- such as free chlorine ions are turned into water soluble chloride.

According to the KDF website, KDF filter media are primarily only to be used for protection against chlorine in water. Apart from that, they can remove, to a limited extent:

  • Bacteria build up
  • Heavy metals
  • Algae growth

What KDF filters definitely cannot do is treat/remove/soften hard water

Additional: Do KDF Filters Remove Heavy Metals?

To a limited extent, KDF filters also protect against water soluble heavy metals by removing them from the water altogether. The heavy metals get plated out on the surface of KDF media.

However, KDF filters are not certified to do so. You see, the efficiency of water filtration through KDF media, and most filters depends on:

  1. The surface area of the filter media
  2. Flow rate of water

Inside a shower filter, which is a pretty small housing, the surface area of the KDF media isn’t large enough to effectively remove heavy metals.

Also, the flow rate of water is too high to filter out a considerable amount of heavy metals.

In industrial applications though, with properly sized filter media and appropriate water flow, KDF media are used regularly for this very purpose.

Do Vitamin C Filters Soften Water?

Vitamin C or ascorbic acid is used to neutralize chlorine in water. That’s pretty much all they can do, so yeah- they cannot soften hard water or remove dissolved salts.

They are, however, the most effective at removing chlorine and chloramines from water. While a KDF filter can treat about 90% chlorine in water, and is ineffective against chloramines, Vitamin C filters remove upto 99% chlorine and chloramines both.

Does Activated Carbon Remove Hard Water Minerals?

Activated Carbon filters work on the principle of adsorption- that is: contaminants stick to the surface of activated carbon. Again, activated carbon is effective against a lot of contaminants such as:

  • Chlorine
  • Chloramines
  • Heavy Metals
  • Trihalomethanes
  • VOCs
  • Pesticides and Herbicides

Overall, it also improves the taste of water and reduces odors.

Activated carbon is able to remove contaminants that are attracted to it’s charged surface or those that are hydrophobic(water hating). Since hard water minerals, such as calcium and magnesium are neither, activated carbon cannot remove them from water.

All right, let’s discuss some constructive solutions. There are a few things you can do to get safe, purified water to shower in.

So Are There Any REAL Alternatives?

  • RO Filter
  • Water Distillation
  • Water Softener
  • CLEO SFU 717 and SFW 815 shower & tap filter(wait… what?)

RO Filters

RO filters are the only effective way to remove hard water salts from water and do so in a timely manner. Additionally, they remove viruses, bacteria, cysts and protozoa from the water as well- better filtration capabilities than any other water purification technology.

You can get a RO filter and simply get a plumber to attach the outlet to your shower plumbing. For your faucets there are several undersink RO purifier models available as well, which are quite convenient. Check out this popular RO filter on Amazon.

Water Distillation

Not a real choice, frankly, but I included it here because it does remove hard water salts- however, the process is extremely slow, and not at all practical.

I can’t think of a good reason for most people to have a water distiller at home, let alone for showering.

Water Softener

A water softener will exchange the hard water minerals- calcium and magnesium- with sodium or potassium(depending on the model of water softener).

While this process doesn’t reduce the Total Dissolved Salts level, it removes those particular minerals which constitute water hardness and in excess, are harmful for the skin and scalp.  

Water softeners are generally quite expensive though- upwards of 500$ with some models running into thousands of dollars.

Also, there are salt free water conditioners that simply treat the hard water salts so that they do not stick to surfaces and form scales. I am not aware, however, whether these also prevent the harsh hard water minerals from sticking to the skin. They are cheaper than salt based water softeners though, and are generally priced around a few hundred dollars.

CLEO SFW 815 and SFU 717 Shower Filter

All right.

Remember everything I’ve said about shower filters not really working for hard water?

Forget that for a moment.

Because this one does. Really, I’m not kidding. I truly believe this is a one-of-a-kind shower filter because it actually works against hard water. It works like a salt free water softener and conditions hard water.

I’ve been personally using the CLEO range of shower filters for close to a year now, and I can attest to that.

No limescale deposits, and the water feels SO much better.

The bad thing for some of you reading this is that these products are only available in India, as of now.

If you are from India- check out my review of the CLEO SFW 815 shower filter and CLEO SFU 717 Shower & Tap filter.

Why Is It Important To NOT Shower In Hard Water?

Prolonged exposure to hard water can cause:

  • Brittle hair and hair fall
  • Dandruff
  • Dull, frizzy hair
  • Weighed down, heavy-set hair
  • Split ends
  • Rashes and dry skin

Most of you are reading this article because you’re probably experiencing one of the above-mentioned effects of hard water.I talked in this post about the 2 most important ways to safeguard yourself from hard water- RO and water softeners.

However, if you are interested in knowing about other ways to maintain your hair and skin with hard water, you may want to read this more detailed post I wrote on the topic.

Hope you found this article helpful- any questions? Jump into the comments section below and I’ll reply ASAP!

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