I just replaced my shower filters, so I thought I’d update my best shower filter review from earlier this year. Each update to the review generates a lot of useful comments. So I’m incorporating what I’ve learned from those comments into this latest review.

Why filter your shower? Well, because your skin is really good at absorbing things. For example, about 60% of the chlorine that is absorbed daily comes from showering in chlorinating water. Because most of us shower under tap water, we absorb things like chlorine, chloramines, heavy metals and VOCs through our skin on a daily basis. Ideally, we’d like to get rid of all of those contaminants. But that’s really only possible if you filter the water as it enters your house using a whole house filter. So most of us are stuck with filtering water at the showerhead, and that’s not optimal. In a shower, the water moves fast and it’s under high pressure. This makes filtration difficult. Also, the water is typically hot, which makes filtration difficult too.

Let’s now look at the three main types of shower filters: KDF (Kinetic Degradation Fluxion) Filters, Carbon Filters and Vitamin C filters.

KDF Filters are by far the most popular shower filters in the U.S. KDF filters remove free chlorine by reversing the electrochemical process that originally separated the chlorine from sodium in a brine solution. However, KDF filters suffer from two major limitations: they don’t perform well in hot water, and they don’t remove chloramines. Chloramine or NH₂Cl (a combination of chlorine and ammonia) now commonly being used in place of chlorine for disinfection. This is because chloramine does not dissipate as easily as chlorine. But this also means it is harder to remove from water. Even the best KDF filters can’t remove chloramine, but they are reasonably effective at removing chlorine. KDF filters last about 6 months. The best rated KDF filters are made by Aquasauna and Sprite.

Carbon Filters are useful for removing certain organic chemicals and chlorine in cold water. Chlorine is attracted to and held (absorbed) into the surface of the carbon particles. However, the efficiency of absorption is basically nullified when the water becomes warm. When used in a showerhead, activated carbon is only effective for a short time — the filter gets clogged quickly by sediment in the water.

Vitamin C Filters are commonly sold in Asia, but they are difficult to find in the U.S. Vitamin C filters are simple — they contain a large block of Vitamin C (ascorbic acid), and water runs through the filter and comes into contact with the Vitamin C. The Vitamin C neutralizes about 99% of the chlorine and chloramines in the water. Vitamin C filters last about 6-12 months, and their effectiveness does not diminish until the Vitamin C is used up.

Here are the chemical equations:

When Vitamin C reacts with chloramine, the byproducts are dehydroascorbic acid, ammonia, and chloride (beneficial to the body).

When Vitamin C reacts with chlorine dissolved in water, the byproducts are dehydroascorbic acid (another form of vitamin c) and hydrochloric acid (in minute quantities).

A fellow who goes by the alias ReviewGuy did an independent test of the different shower filters, you can read about his results here.

Vitamin C filters are really the only type of shower filter than works consistently, especially if your water contains chloramines. Unfortunately, many Vitamin C filters are cheaply made. Here’s my review of the different products available:

Sonaki Vitamin C Handheld Showerhead Chlorine Filter

Sonaki Vitamin C Showerhead Filter

The Sonaki Vitamin C Handheld Showerhead Chlorine Filter has the best build quality I’ve found. It costs about $90, and it comes with a low-flow showerhead. The showerhead has two spray patterns and an off  switch. I like the feel of this showerhead, and the fact that the filter is transparent, so you can see when the Vitamin C has run out. It also comes with two replacement Vitamin C cartridges. It’s available from Amazon for $90.

Sonaki VitaMax Vitamin C Inline Filter

Vitamax Inline Vitamin C Shower Filter

The Sonaki VitaMax Vitamin C Inline Filter is a good choice if you already have a showerhead you like. This filter fits in-line and works with your existing showerhead. It costs about $50, and it’s available from Amazon.

In my home I currently use a Sonaki inline filter attached to a Culligan shower filter (this is an expensive charcoal shower filter). This combination looks makeshift but it works quite well once installed. The Sonaki filter is for chlorine and chloramine removal, and the Culligan filter is to remove scale, rust and other contaminates.

Update: Here’s a study on ascorbic acid and chloramines.

Thanks to Darren and SteveG for their research.

Note: Please stop read this article, and read our updated shower filter article instead

I wanted to post an update on my quest for the best shower filter. I received a lot of useful comments on my last shower filter post, and I’ve also tested a couple of new shower filters.

The shower filter market is huge, and sales are dominated by shower filters that use KDF (Kinetic Degradation Fluxion). However, KDF filters don’t actually perform well as shower filters. They often get clogged after a few months of use. Also, they don’t perform well in hot water, and they don’t remove chloramines (which is commonly used in place of chlorine in tap water). Also, KDF filters are also affected by water pressure. When the water pressure is not high enough, water can’t pass through the KDF powders.

I haven’t found any formal comparative tests of shower filters. One independent reviewer “ReviewGuy” tested eight popular filters with a chlorine test kit in 2006. About his tests, he says:

Tests include before and after total residual chlorine levels using a digital chlorine meter to measure the results. The shower filters are tested for their ability to remove total residual chlorine in an actual residential shower unit.

You can read about his results here.

The best performing shower filters were: two Vitamin C shower filters, and the Sprite Shower Filter — these filters removed about 99% of the chlorine in the water. (He didn’t test for the removal of any other contaminants.)

ReviewGuy concludes by saying:

I welcome any of my readers to verify or debunk the claims I have made in this comparison by conduction your own independent research & testing. This is an open invitation that includes everyone from the end user to shower filter manufacturers. To date, there has not been a single person or company that can or will refute my data.

However, there are a few new shower filters that have appear in the market since 2006. In my opinion, the best shower filters today are combination filters that use both Vitamin C filters and chlorgon or ceramic filters.

What is Chlorgon? It’s a combination of calcium sulfite with a ceramic binder to form non-soluble ceramic sulfite beads.

Vitamin C (ascorbic acid) is really the best at removing chlorine and chloramines. It removes 99% of the chlorine in both hot and cold water, and Vitamin C filters last about twice as longer as KDF filters.

But Vitamin C filters only neutralize chlorine — they don’t filter out anything else in shower water. To remove VOCs and heavy metals, you have to add a ceramic or chlorgon filter. See the detail in the shower filter update.

This post has been updated for 2011.

I recently wrote about Filtering Your Drinking Water Very Efficiently, but let us turn now to your shower water. When we shower, we absorb the substances dissolved in water through our skin quite readily. For example, 60% of the chlorine absorbed daily comes from showering in chlorinated water. The chlorine is absorbed directly from the water and from the chlorine gas released into the air.

Ideally, we would filter out all the undesirable chemicals from our shower water. However, unless you have a whole house water filter, this is not possible. This is because filtering water at the showerhead is problematic — the water moves fast, making filtering difficult, and the water is typically hot, which is also undesirable for filtering.

So basically, if you are filtering your shower water at the showerhead, you can only really hope to remove chlorine from the water. Shower filter manufacturers who claim otherwise should probably be viewed with skepticism. But chlorine is certainly one of the first you’d want to remove from your shower water. Anyone who has swam in a swimming pool with high levels of chlorine, can tell you that it dries and irritates the skin, makes  hair brittle, and causes eyes to become red and itchy. Also, inhaling the toxic steam can aggravate the sinuses and lungs. But it’s not only chlorine that’s in municipal water these days, increasingly cities are adding chloramines to the water. Chloramines are more stable compound, containing chlorine and ammonia. Unfortunately chloramines are more difficult to remove from water.

However, there are filters out there that will remove 100% of chlorine and chloramines from your shower water: vitamin C-based shower filters. These filters have a simple method of operation: the shower water passes through the block of vitamin C, and the chlorine is converted to inorganic chlorides. Vitamin C shower filters are made by a few companies, for example VitaC Shower, Keosan and Sonaki. You can also get filters for your bath too.

Another common type of shower filter is the KDF filter, which uses copper and zinc for filtration. KDF filters remove free chlorine by reversing the electrochemical process that originally separated the chlorine from sodium in a brine solution. KDF filters, however, have a important limitation: they do not remove chloramines. Also, KDF shower filters are affected by water pressure. When the water pressure is not high enough, water can’t pass through the KDF powders. KDF filters also tend to get clogged very quickly. I’ve seen some buyers on Amazon reporting that their KDF filters get clogged after a couple months.

Some shower filters use activated carbon. This is effective in reducing certain organic chemicals and chlorine in cold water. Chlorine is attracted to and held (absorbed) into the surface of the carbon particles. However, the efficiency of absorption is quickly nullified when the water becomes warm. The lifetime of an activated carbon shower filter is very short. An activated carbon shower filter gets clogged very quickly by the dirt it is meant to stop.

So I recommend a vitamin C shower filter like the VitaC Shower brand filter. I’ve used these filters for years, they remove 100% of the chlorine and chloramines from your shower water, and will last about 6 months before they need replacement.

Recently, municipalities around the world have begun to use
chloramine (a mixture of chlorine and ammonia) to disinfect water. This
is done to reduce free chlorine’s ability to combine with organic matter
in the water thereby producing potentially harmful trihalomethanes, or
THMs. Because chloramine has less disinfecting ability than free chlorine,
a higher concentration of chlorine is usually used to get the same bacteria
kill rate. Yet chloramine’s harmful effects are the same
as pure chlorine, so the hazards while showering are greater.

Carbon has long been used to absorb
impurities and is perhaps the most powerful absorbent known. Activated
carbon is carbon which has a slight electro-positive charge added to it,
making it even more attractive to chemicals and impurities. As the water
passes over the positively charged carbon surface, the negative ions of
the contaminants are drawn to the surface of the carbon granules.

Activated carbon filters are usually rated by the size of the particles
they are able to remove, measured in microns, and generally range from
50 microns (least effective) down to 0.5 microns (most effective).

The most common carbon types used in water
filtration are bituminous, wood, and coconut shell carbons. While coconut
shell carbon typically costs 20% more than the others, it is generally
regarded as the most effective of the three.

Advantages:

• Good filter for improving taste and odor, chemicals and some cysts.

Disadvantages:

• Bacteria can multiply in filter
• Doesn’t last long with hot water
• Doesn’t perform well at high temperatures,
  needs other technologies to work as shower filter.

This bath filter removes 90% or more of free chlorine, improves lathering with quartz crystals.

You swirl in the bath water for a few minutes, for filtration to occur.

Available from: Natural Baby or Ebay