Comparison of Water Filter Systems

The task of a good water filter is to remove all the unwanted pollutants and contaminants from your drinking water. But it should do more than that. A good water filter will also support your health by preserving the healthy minerals, such as calcium and magnesium.

There are various filter systems availble on the market, and it can be difficiult to find out which system is the most suitable for your needs. Below, you will find easy-to-understand explanations how these individual filter systems work, and what performance to look out for to find the best home water filter for your requirements.

Multi-Stage Filter with Activated Carbon

Due to the wide variety of contaminants in tap water, a single method is not sufficiently effective to remove them all. What you need is a multi-stage filter consisting of the following:

A good water filter will start by removing sediments and turbidity first, i.e. particles that may cause cloudiness and unpleasant, often metallic or 'muddy', tastes in water. While these may not necessarily be unhealthy, they will spoil your enjoyment of drinking water.
The next thing it will do is reduce chlorine, the most concentrated chemical in tap water.
The next filtration step involves an ion-exchange filter to remove heavy metals, particular lead, which might still come from old water installations using lead pipes. Ion-exchange is the most effective modern method to take up lead from the water and to substitute it with potassium, one of the healthy minerals in clean drinking water.
The main filtration stage is carried out by a granular activated carbon filter to absorb synthetic chemicals such as herbicides, pesticides and industrial solvents.
A final sub-micron filter is build-in to reduce chlorine resistant micro-organisms such as Cryptosporidium and Giardia, common water borne parasites.
We consider multi-stage water filtration to be the best state-of-the-art water filtration method available, and for this reason we highly recommend them.

Reverse Osmosis

Natural osmosis is a process in nature that transports water across a membrane, for instance up the stem in plants and trees.

Reverse osmosis is a technical process, whereby pressure is applied to the water on the impure side of a semi-permeable membrane. The membrane has sub-microscopic small holes which will only allow small substances to pass through. It will therefore hold most of the salty impurities back, i.e. calcium, magnesium, heavy metals and more; and the water on the other side of the membrane will be purified. Unfortunately, some of the contaminants and pollutants of tap water, such as VOCs, can still travel through the membrane. For this reason, most reverse osmosis water filter systems have a carbon filter integrated. However, this method removes the vital minerals calcium, magnesium, and potassium from the drinking water, a severe downside of this water filtration method. (Historically, reverse osmosis was, and still is, used to do especially this - to demineralize water for industrial processes or desalinate sea water.) Another drawback is that reverse osmosis turns only part of the water into filtered water, and the greater part of the incoming water is wasted. Due to the restriction of the membrane, the filter process is slow and requires a tank to store the filtered water, for it to be available at the faucet on demand. The maintenance of reverse osmosis water filter systems is also higher than that of other filter systems.
Because reverse osmosis removes the natural beneficial minerals calcium and magnesium from the drinking water, it is not recommended.

Water Destillation

One extreme way to purify water from any inorganic contaminants, i.e. minerals, salts, and heavy metals, is destillation. However, this process does not remove volatile organic pollutants, and you would need a carbon filter as a second purification step. Many health practitioners consider destilled water unsuitable for drinking, as it lacks all the minerals, such as magnesium and calcium, which are vital for good health.
We agree with them and do not recommend water destillation.

Filter Effectivity

Regardless whatever brand of filter system you choose for your domestic drinking water, one important piece of information you should ask for is the effectiveness of the filtration process, i.e. how good the system is at removing contaminants. Any reputable manufacturer will have his systems tested and certified by an independant organisation such as Underwriters Laboratories.