Expert tests of water filters: which are better

Do I need a water filter at home? Probably, this question arises less and less, since tap water in our houses and apartments does not always shine with quality. The question arises in which filter to buy. Is a simple filter jug ​​enough? Or is it worth installing a flow-through system with several cartridges? Or maybe install a reverse osmosis filtration complex? Let’s figure it out in more detail using laboratory tests.

Test Participants
Water for testing was taken from the central water supply system of Vladivostok, therefore the test results in terms of indicators describe the situation with water in this city. In other settlements, water may differ in composition of chemical elements, degree of hardness and other characteristics.

For the comparative test, one type of filter of each design was selected. Models take part in testing:

At the same time, the tests carried out clearly show how the filters cope with different impurities, so it is quite possible to focus on the results obtained when choosing a filtration system for your house or apartment.

 

Water analysis was carried out at the Center for Hygiene and Epidemiology of the Primorsky Territory, which has the necessary equipment for comprehensive testing in terms of the content of inorganic substances and organic compounds. For comparative testing, the most common and popular tests have been selected to clearly show the differences between different types of filters. Let’s see what happened in the end.

Organoleptic testing
From organoleptic indicators, odor, color, turbidity and taste were tested.

According to the test results, it turned out that the water from the jug and the water supply has an increased indicator of turbidity. It is possible that the increase in turbidity after filtration in a jug is due to the insufficiently rinsed new cartridge before use, although its preparation for the test was carried out strictly according to the instructions. But in any case, all indicators were within the normal range.

 

The color and turbidity after passing the water through the flow filter and the reverse osmosis system are significantly reduced. This suggests that these filters retain much more colorants from tap water.

Please note that in non-standard situations, for example, after replacing pipes or repairs, turbidity and color can increase to such an extent that poor water quality becomes noticeable to the naked eye. In this case, you should not experiment on filters, they will simply clog.

Chemical Purification Testing
Nitrate content
Nitrates can enter water in areas with developed agriculture due to leaching of fertilizers.

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In the tested water sample, the nitrate content is initially significantly lower than the permissible level, with water everything is in order. After the water passed through the filter jug, the amount of nitrates was more than halved. And after a flow-through filter and reverse osmosis, they are practically gone.

According to the results obtained, it is clearly visible that the filters cope with the task of removing nitrates, therefore, in those areas where these chemical compounds are contained in the water, filters are required.

Chloride content

It was not possible to accurately determine the degree of filtration of chlorine compounds, including ordinary food salt, which is sodium chloride from the point of view of chemistry. The content of chlorides in tap water was so insignificant that it did not change after passing through the filters.

Testing for total hardness, calcium and solids
During this test, the water hardness was checked. It is hard water (calcium and magnesium salts) that forms scale in household appliances and is the source of all the problems associated with them. The dry residue is also an indicator of mineralization. In the event that it is more than 1000 mg / l, the water is considered mineral.

 

It turned out that the water taken for testing is quite soft and its overall hardness is negligible. In addition, filters further reduce it. And best of all, this is done by a filter with a reverse osmosis installation. He also copes best with the dry residue. It should be noted that the result obtained for filtered water after reverse osmosis is the result of mineralization already in the filter. The fact is that the reverse osmosis membrane in this filtration system completely filters all mineral compounds.

Testing for pH value
The pH value determines whether the medium is acidic or alkaline. It is generally accepted that water with a pH of less than 6.5 is acidic, and more than 8.5 is alkaline. At the same time, water with a neutral pH is optimal for humans. The ideal option is when the pH is 7.4, since our blood has such a pH.

 

But it is clear that this is the ideal case. Therefore, for water, the pH value is considered normal in the range from 6 to 9. It turned out that all filters, except for the reverse osmosis system, keep water within specified limits. After passing through the reverse osmosis filter, the water became alkaline. This may be due to the fact that the membrane allows certain types of ions to pass through, but blocks everything else.

Testing for phenol and traces of petroleum products
A large amount of phenol and petroleum products can indicate the ingress of wastewater into the water supply system. Since these substances are toxic, they must be filtered. The amount of phenol and petroleum products in the tested tap water was at a minimum level, which indicates that the wastewater does not enter the water intake or the water filtration system is working efficiently.

 

Filter manufacturers claim that their systems filter phenol and petroleum products, but the test failed to determine the degree of filtration due to the low content of these substances.

Testing for the presence of chloroform and its compounds
Chlorine compounds are used for disinfection, but at the same time, chloroform in large quantities is harmful to the body, therefore, if it is present in the water, these chemical compounds must be filtered.

 

Almost all chlorine compounds in the water tested were at minimum levels, with the exception of chloroform and bromodichloromethane. All three filters successfully coped with these connections. The best results were shown by reverse osmosis.

Toxic element filtration testing
Lead, cadmium, copper, manganese and other not very useful elements of the periodic table get into tap water from natural sources and industrial effluents. They must be fought with, since the accumulation of these substances in the body does not lead to anything good.

 

In the test carried out, an overestimated content of manganese was found, but at the same time it was below the permissible norm. However, all three filters successfully filtered this element, significantly reducing its content in the water. The filtering results for all three filters were comparable.

The presence of common iron
An excess of iron in water cannot be called useful and can be associated with both natural and man-made factors, for example, rusting of pipes. In our case, the water was found to have an increased iron content – it was more than normal.

 

During the test, it turned out that the pitcher filter does not cope with the filtration task. This is not surprising, since a special cartridge, not a universal cartridge, must be installed to filter iron. An in-line filter and a reverse osmosis system filter iron without problems.

Microbiological testing
Microbiological tests provide an overall assessment of the quality of the cleaning performed. Before testing, a mistake was made – the period for supplying water for microbiological testing after its sampling was exceeded and measures were not used to prevent the ingress of bacteria during sampling. In addition, a standard cartridge was used in the filter jug, although there are specialized ones that provide protection against bacteria. If you have problems with microbiology in the water, then it is worth buying just such for jug ​​cartridges.

 

Nevertheless, despite the mistakes made, the test results showed that the flow filter and the reverse osmosis system successfully purifies water from microbiological impurities.

conclusions
Water filters actually perform additional purification of tap water from harmful substances. Considering that our water is different and not always of high quality, the use of filters is an absolute must.

It should be borne in mind that filter jugs have a limited capacity and are equipped with only one cartridge, which must be selected depending on the specific physical and chemical properties of water. To increase softness, it is more convenient to use a main filter.

It is possible that the water can be so hard that a regular flow filter cannot cope. Then you should think about installing a reverse osmosis system. In any case, the choice of a specific filtration system and the types of filters used depends on the composition of the water in a particular area.