Do Water Filters Work? An expert insight

The short answer is a resounding yes. Otherwise, we’d all be drinking infected water and getting ill very frequently, just as people did years ago.

Cleaning up water at the municipal level for a public water supply is very similar to having a water filter in your home. The main differences are scale and what is used as the filtration medium.

Of course, different filter media and methods are used to remove varying infections and contamination.

Let’s look at a few of the issues around water filtration in more detail. Let’s start by explaining how a water filter works.

How does a water filter work?

It’s a simple question but not necessarily a single easy answer.

At its most basic a water filter works by passing water through a permeable barrier leaving unwanted items within the filter. That could be by creating a physical barrier, such as a sediment filter, or a reaction, such as a scale reduction filter.

Some water filters aren’t strictly filters at all even though they perform a similar function, for example a UV filter.

That simple answer now leads to more specific queries such as if a type of water filter works better than others.

So, let’s look at the most common types of home water filtration and answer some of the questions we get around the different types of systems and their effectiveness.

Do alkaline water filters work?

There are two parts to this answer.

The first is that alkaline water filters DO work to produce water that it is 8 to 10 pH. In that regard they do work.

The second part answers the implicit intent of the question “do alkaline water filters work to improve health?”.

It’s not a good idea to be drinking highly acidic or alkaline liquids, but there’s a range that’s closer to neutral that’s considered safe by medical experts and government health authorities alike.

Some people say that consuming alkaline water can help neutralise acid in the body. This is said to improve the immune system and boost hydration.

There may also be benefits for bone health, however, this is likely due to the minerals calcium and magnesium being used to make water more alkaline being absorbed by the body.

It’s not the fact that the alkalinity helps, but the dissolved minerals are the ones that make the difference.

The same is true of the claim that alkaline water helps prevent and treat kidney stones. It’s the calcium bonding with the oxalates that are present in kidney stones that’s effective.

On the other hand, the stomach contains highly concentrated hydrochloric acid. So, when mildly alkaline water enters the stomach, it’s immediately neutralised.

The problem with giving a definitive answer is that there just isn’t enough independent research data available. Very few large studies have been done to support or debunk the claim.

Do carbon water filters work?

The effectiveness of carbon water filters has a very definite answer – carbon filters work very well and are highly effective. There are various forms of carbon filters.

Carbon filters tend to be made from coconut shells or bitumen and be in either granular or block form. They are also generally regarded to be more efficient than granular activated carbon (GAC). This is because water can create channels through the granules, during prolonged use, leading to lower contact time of water to carbon medium. It’s an efficiency thing.

And as it happens, carbon block filters are actually made of granular activated carbon pressed together to make the block.

The micron rating of a carbon filter is less important than with sediment filters. The way they work is ADSORPTION (yes, adsorption, that’s not a typo). This is where the compounds and molecules of the contaminant stick to the carbon molecules within the carbon block filter medium.

However, as with all cartridges, the one drawback of carbon block cartridges is that when they’ve reached the end of their working lives they need to be replaced. Whereas granular activated carbon in larger filter vessels can be regenerated to extend the life of the medium for up to three years. However, this type of filter is usually more suitable for commercial rather than domestic applications.

If you want this type of carbon filter look for the term “backwash” in the specifications.

In summary, do carbon water filters work? Yes, but you need to know what the best one is for your needs.

I can hear you saying, “that’s all very good but do charcoal water filters work better?” The truth is that charcoal water filters are very similar to carbon water filters, but the material they are made from is different. Charcoal water filters are effective, but activated carbon filters are more efficient at filtration due to being more porous than charcoal.

Do filtered water bottles work?

Filtered water bottles are not a recent invention, but they have improved drastically over the last few years.

Most are designed to filter out the same things as carbon water filters. But in addition, they also remove bacteria, cysts, and other microorganisms out of water from streams, ponds, and rivers making the water safe to drink.

These kind of water bottles are ideal if you’re out adventuring in the wilds. They give you the comfort of knowing that if you run out you can still make your own potable water supply.

Although filtered water bottles are more expensive than filling an ordinary bottle from your drinking water filters at home they are well worth the extra cash. In an emergency you’ll thank yourself for the purchase.

On to the next regularly seen question…

Do fridge water filters work?

Much like the other water filters we’ve looked at here, a fridge water filter does the same job, but is specific to low flow rate chilled outlets in refrigerators.

They come in a variety of forms. They may be generic or branded to match the specific make or model of refrigerator you have.

These types of filters work as well as any other carbon filter, and some have scale reduction elements in them too.

One of the advantages with a fridge water filter is that they often also supply water to an integral ice maker. The great news is that the resulting ice has a pristine quality to it that you just don’t get by filling up a tray with water from the tap and putting it in the freezer compartment.

Having hinted at scale reduction, let’s move on to a final enquiry we often get.

Do hard water filters work?

Treating hard water is not easy, but it can be done. The usual method is to use a water softener. These replace the hard ions – calcium and magnesium carbonate – with sodium ions.

The problem with that is that it means there’s residual sodium left in the water, so it’s not ideal as drinking water due to heart health risks. In addition, you need to have an electricity supply and drain so that the regular backwash can take place to regenerate the resin medium. Then there’s the weekly addition of salt blocks to add.

But water softeners do work well to remove the hardness.

There are other methods though. Let’s just take a step back and look at this from a different angle.

The problem usually isn’t that the water is hard, it’s that the scale builds up in appliances, ruins shower heads, and makes skin and hair feel unpleasant.

In fact, going back to the beginning, removing the calcium and magnesium carbonates means taking away minerals that are vital for our health.

Both minerals are important for bones and teeth, as well as the keratin in our hair and nails, among other things.

Having said that, you should ensure that you have plenty of these minerals in your diet too.

With that established why not treat those dissolved minerals instead of removing them.

That's exactly what hard water filters do.

The low-cost method is called “sequestration”. This is where a food grade polyphosphate compound is gradually introduced into the water supply to inhibit the formation of limescale.

While it can work well in medium hard water areas it’s not so good where the water is classed as hard or very hard, let alone extremely hard.

A more modern innovation is template assisted crystallisation (TAC). These are becoming more common and have been around since the early 2010s. TAC works by passing cold water through a sand like filter medium where the water circulates within a filter cartridge or vessel. The dissolved minerals interact with the TAC media on “crystallisation sites” where they form microscopic crystals that then break away and then just flow through the plumbing with out sticking and forming scale.

It’s a totally physical process, no chemicals are added to the water, the maintenance is low with an annual filter cartridge change, and no electricity or drain is required.

Conclusion

That’s a selection of some of the burning questions many people have when they are considering buying a water filter.

There’s a lot of information available online, not all of it is sensible or based on real world knowledge and experience. All the water filters we’ve mentioned work well for most people but there are always specific circumstances that mean that the solution for one person may not be correct for another.

So don’t be shy, get in touch with Fountain Filters and we’ll answer your queries and point you in the right direction as to which water filter is right for your needs. You will end up with a water filter that works for you. There are no stupid questions when it comes to water filtration.