How to Choose Water Purifier for Your Home
The quality of water supplied to Indian homes is undoubtedly very poor. Full of contamination and impurities, it is unsuitable for drinking and cooking. Given that, most households, especially urban India, are increasingly getting dependent on a water purifier to fulfil their drinking and cooking needs.
However, choosing a water purifier is no mean task. Not only are innumerable brands and models available, but they also differ vastly in the technology used, levels of water purification, the water wastage and several other considerations.
Keeping that in mind, we list out a few important considerations that you must know to rightly shortlist the most appropriate water purifier for your home. Stay hooked!
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Understanding water impurities and contamination
Before you begin to even hunt for a water purifier, it is important to understand the quality of water coming out of your tap. For it, you must first have a good knowledge of the water impurities and those present in your tap water.
The type of impurities present in the water is predominantly decided by the source from which the water is coming. The major water sources are water rivers, lakes, bore wells, municipal corporation water supply, water tankers, harvested rainwater, etc.
Now let’s understand some of the most common type of impurities.
Constituting of mostly mud and sand, they are found in river, bore well or damaged pipe water. They make the water look turbid or muddy.
Dissolved inorganic salts
Mostly found in bore wells and seawater, they are mostly sodium and potassium salts. They make the water taste extremely salty and brackish.
Dissolved inorganic compounds
These are calcium and magnesium compounds that decide the hardness and scale formation ability of the water. Its major water source is bore wells and river and lake water.
These can be sulfates, bicarbonates and other compounds, which are mostly found in lake and pond water and even in water from other sources. They impart a foul and bad odor to the water.
Most bacteria and virus fall under this category. These mainly thrive in damaged pipe water, water tankers, etc. These impurities are responsible for causing water-borne diseases, and other biological contamination.
These are traces of chemical present in treated water. Primarily Chlorine, they are present in Municipal supplied water and impart a bitter taste to it.
Apart from it, you can also find some poisonous chemicals, mostly lead and arsenic that can prove fatal for life.
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Understanding the TDS level
TDS level of water is the most common term you would come across when choosing a water purifier. Standing for Total Dissolved Solids, it refers to the total amount of inorganic salts and organic matter present in the water solution. They are primarily calcium, magnesium, potassium and sodium cations and carbonates, chloride, sulfate, hydrogen carbonate, iron, and nitrate anions.
The TDS of water is measured in mg/liter or parts per million(ppm). Going by the standard, drinking water must have a TDS below 200 ppm. However, the water still needs to be purified to eliminate harmful bacteria and virus.
Once you have understood the above two criteria, you need to assess the quality of water that comes into your house.
It might be hard to know the source of water though most urban areas have water supplied by the Municipal Corporation.
The next step is to test the water coming from your house tap. A water test kit or a TDS water meter would help you know the TDS level of the water. You can even smell and taste it to have a rough idea of the contaminants. A bad smell, salty and bitter taste are all indicators of water not fit for drinking.
But the best way to truly gauge the water quality is to send a sample of it for detailed analysis in a water testing lab. It will give you a clear idea of all impurities present in water. The result would play the most important role in deciding the best water purifier.
Mapping results to water purification technology/purifiers
All contaminants and impurities cannot be removed in a single and straightforward treatment. Each one requires a different technology. The impurities of the water would decide the technology used in your water filter and thus its type. The leading water purification technology used are:
This technology works best to purify water with high TDS level. Purifiers using this technology pass the impure water at high pressure induced by the pump into a RO chamber having a semipermeable membrane. The membrane has innumerable pores of size about 0.0001 microns.
When the water molecules pass through the membrane, the difference in osmotic pressure forces it to leave dissolved solids and impurities behind and come as pure water on the other side. The impurities left behind are washed away with little water and eliminated via a different reject line.
The RO technology can effectively eliminate all salts and impurities, and all bacteria to significantly reduce the TDS level.
However, this technology has a recurring electricity cost, causes plenty of water wastage (approximately 3 litres of wastewater per litre of purified water), and might need yearly membrane change, depending on the TDS level. It must also be noted that this process can also remove the essential minerals from the water which imparts its taste and are good for health.
This technology also uses a membrane but its membrane pore size is much larger of about 0.01 microns. Here water can pass through the membrane using the natural force of gravity. Hence, it can eliminate all undissolved impurities but not the dissolved ones. Moreover, it is the sole technology that is certified to eliminate cysts.
This is a fast filtration process that does not need electricity to generate force because of the large pores of the membrane. They can act as a barrier to bacteria and virus but cannot reduce the TDS level significantly. It is also incapable of eliminating heavy metals and pesticides.
UF water purifiers are best used where water TDS level is low. However, further disinfection of the purified water is strongly recommended.
Activated carbon water purifier
It is made up of charcoal granules that can easily absorb pesticides and herbicides. With no use of electricity, they can even eliminate chlorine and improve the taste of water.
Considered a basic filtration system, they are highly popular as tap-faucet mounted filters. Here, the water is made to pass through a sediment filter or sediment filter and activated charcoal filter to remove bad odor and improve the water taste.
This technology is a fast method to disinfect the water. It uses an ultraviolet lamp that can effectively neutralize all virus, bacteria and similar contaminants. But this process cannot remove any dissolved chemicals and solids from the water.
The process cannot reduce the TDS level and thus is ideal for water with low TDS and almost pure water. It does not require any electricity and needs low maintenance. However, the UV bulb needs to be changed every six months.
The right purifier
Generally, for TDS level below 500 ppm, you can choose UV and gravity-based purifiers and UF depending on presence/absence of biological impurities. For TDS level above 500 ppm, RO purifiers are recommended.
Predominant areas of India receive water with high TDS. Consequently, the RO filters have become the face of water purifiers in India. But as none of the purification process is complete by itself, most water purifiers come with a combination of technologies especially a combination of RO, UF, and UV.
Each filtration process is referred to as stages. Today, leading water purifiers give you 5-6 stages of filtration to eliminate all kinds of dissolved and undissolved impurities including harmful contamination. You can select according to the water quality.
Water purifier’s storage tank capacity
Post deciding the technology, you need to think about the filtered water storage capacity of the purifier. It will be the volume of water that would be available to you at one go. If your area faces power outage, you need sufficient volume of water to last for a few hours.
Generally, singles and couples need 4-5 litres of stored purified water. Small families of 3-4 members can live comfortably with 6-8 litres of stored water while larger families need anything from 10 litres and above.
Type of water storage tank
Most filters come with either a steel tank or a plastic tank. You need to choose between the two. Stainless steel tanks are touted as better and safer.
Even though the plastic used in tanks is food-grade, bacteria and germs can breed again in plastic tanks. Moreover, the cost of the purifier spikes with a steel tank. If you are using the filtered water every day, and throughout the day, you can choose the plastic storage tank.
Design and build-up of product
Apart from tank, the size, design and other aspects of the purifier are also important. It must be robustly built and guaranty safety and durability. Materials used should be sturdy and safe for use.
Water filters come in varied dimensions and are often bulky. Many require electricity and an inlet and water outlet feasibility. A certain water pressure is also needed. Areas of low water pressure might need an extra water pump.
Hence, it is important for you to gauge the installation feasibility before purchasing the water purifier.
The non-electric purifiers are cheaper than the electric ones. They mostly have UF technology, sediment filtration and carbon filtration that can work with water with low TDS value.
For water with high TDS value, you have no choice but to choose the electric filters.
The certifications received by the brand is another important consideration. Certifications like NSF, WQA, CE, ISI, etc., assure you about authenticity of the brand and the product.
Warranty, maintenance cost and after-sales service
Water purifiers need regular maintenance and change of membranes and filters at regular intervals. This makes all mentioned parameters, a vital consideration. You need good service as well as reasonable annual maintenance contracts, and proper warranties to get the maximum out of your water purifier.
We hope that by now, you understand all the major features and considerations for a water purifier. Going by this checklist, you are sure to nail the most appropriate water purifier for your home.
Do chime in below for any suggestion or queries!