Currently there are multiple water purifiers available in the market. All water purifiers have their own USPs and all claim to give the best water quality. However, what you need to keep in mind is that all water purifiers come with different technical specifications and have certain basic requirements. Knowing which one will work for you, depends on factors like water pressure, water quality and space available and if you are unsure which one you should go for, then take a look at this guide that will help you select the best water purifier for home use.

Different types of water purifiers

Water purifiers for the home are classified into two broad categories: non-electric storage types which work on gravity, and online types which work on electricity. While both need water, the latter needs running water for it to work. However, storage of purified water, either within the purifier or in another container makes the usage on an online water purifier possible, even if water is available a few hours a day. The advantage of an online variety is that it normally works on UV or RO technology, both of which are chemical free.

Different types of water

Is your water surface water (from rivers and lakes) which has been supplied by the municipality or is it ground water ? (from borewells, supplied by tankers). If it is surface water, supplied by the municipal corporation, chances are that the TDS (dissolved impurities) are low and you need to only protect yourself from microbiological impurities like bacteria and viruses. However, if your water is ground water supplied by tankers, there may be a higher level of dissolved impurities, altering the taste of the water, and at higher levels may affect your long term health.

As a thumb rule, if you get ground water, check the TDS with a simple TDS meter. If your TDS is above 500 ppm , then choosing an RO water purifier may be beneficial. If the TDS is lower than 500 ppm, then a well designed UV purifier will be effective in purifying the water. Most companies selling water purifiers do this simple TDS test. It is important to note that using a RO water purifier where TDS levels are low, say under 200 ppm, may be detrimental to your health in the long run, as the water is stripped of essential minerals and salts. There is also substantial wastage of water (upto 80%) in a RO purifier, so unnecessary usage is wastage of a valuable resource.

Water Pressure

Understanding whether you have sufficient water pressure while using an online water purifier is important. Online water purifiers normally need a pressure of between 5-40 PSI (pounds per square inch) for them to work effectively. An easy way to calculate the pressure in your tap is to see how many floors you are from the terrace from where water is distributed by gravity. So if you are in a 10 story building and you live on the 8th floor, then your water pressure is likely to be 10PSI, because every 10 feet from the top is equivalent to 5 PSI. If you live on the 1st floor, then the pressure in your tap will be around 45 PSI. In that case a pressure reducing valve will be required along with the online water purifier.

For homes with very low pressure, a booster pump will help or alternately a UV purifier which works on loft tank pressure can be opted for. Alfaa UV’s PLATINA water purifier works on loft tank pressure, and makes it an attractive option in homes where the pressure is low. .

Location of Water Purifier

Locating the water purifier near a source of water and an electrical point with earthing is important. Ideally the distance between the purifier and the water / electrical point should be within 3 feet. Also keep the purifier away from direct heat or sunlight. If space is an issue, or if you would like to keep your counter space empty, opt for a wall mounted purifier. In most cases, apartments today provide a special water outlet near the sink in the kitchen to which the purifier can be easily connected.


Please understand that fundamentally an online water purifier, whether UV or RO needs regular servicing and replacement of critical components. Service needs match water quality. The poorer the water quality, the more frequent the service required. So check service availability in your area and the credentials of the service provider.