With the oncoming rains, consumers are increasingly on the lookout to buy the best water purifiers in the market. But even the high temperatures that consumers have been enduring this summer present ample scope for impurities to fester in water.

The introduction of various brands of water purifiers has made the entire process of water purification comparatively simpler. On the other hand, it has also complicated the process of choosing one from amongst various brands in retail stores. The popular belief is that the key differentiator for most such purifiers is the technology used.

However, one of the most critical aspects is to recognise the type of certification mark on these purifiers in addition to identifying the type of purifier required on the basis of various water types.

Decoding certifications

Broadly, water purifiers have one or two of the following certifications. The IS 16240: 2015 standard covers Reverse Osmosis (RO) based point of use (POU) water treatment system with a capacity of up to 25 litres per hour that reduces the total dissolved solids (TDS) of water, reduces chemical contamination to safe level and removes physical particles including microbiological impurities. This is the most common type of water purifier being used by urban households. RO technology combined with sediment filter and carbon filter has proven to be an effective water treatment method for removing various inorganic, organic and microbiological contaminants from the water. Realising the fact that many organised and unorganised sector companies have launched their RO technology-based water treatment in the market, BIS has recently launched this standard and consumers must look for compliance with this standard before making their purchasing decision.

The other standard is IS 7402:1986 /2011. This certifies that the ceramic filters used in the purifier can arrest impurities to the finest range possible, including particulate and bacterial impurities. This standard also signifies the presence of a silver filter cap that has the highest germicidal capabilities. Most replaceable ceramic filters in the market do comply with this certification. However, the market also has an innumerable number of brands that do not conform to this standard and can pose a potential risk to the users.

The IS 14724: 1999 indicates that the purification process is carried out through a combination of UV film and rays. UV films in this case are of pre-specified thickness and durability. These UV films are also certified to remain unaffected even after continued contact with water. Another aspect that is covered in this certification is the intensity of UV rays. These rays tend to lose strength over a period of time and are a key differentiator of quality among the various brands available but the certification ensures durability as well. A UV purifier without this certification can be cheaper, although its effectiveness fades with time.

In addition to the above three certifications, IS 10500:2012 gives an assurance of the quality of the water to be consumed directly. It signifies that the end product is free from coliform, pesticide residues and other chemical contaminants. This certification is present on all good quality water purifiers irrespective of the process of purification followed. There is also a possibility that one of the above certifications is present, but the quality of drinking water is not certified. It is important to note that this too can pose a risk to the consumers.

Choosing the right purifier

The right type of water purifier is determined on the basis of the type of water running in household pipes and determining this type can be challenging. The ideal way is to get samples tested in a laboratory. However, a more pragmatic and home-grown way is to identify the source of water. Water is either sourced from borewells or through the municipality which in turn treats water that it sourced from various water bodies. Municipal water is pre-treated to eliminate impurities and most impurities make their way through water through old pipelines and various other transport and storage systems. Ground or borewell water varies in quality depending on the surroundings. Within city limits such water has more salts and microbiological contaminants. Similar water in the vicinity of industrial belts may contain industrial pollutants such as arsenic.

The most cost-effective water purifier type is the one with active carbon filters that safeguard drinking water from chlorine, pesticides and herbicides that are eliminated by the presence of carbon granules. These are ideally recommended for underground or boring water in areas that are far away from industries and not in highly urbanised areas.

In areas, especially urban and semi-urban, where water is sourced from the ground, RO (reverse osmosis) purifiers are preferred. They help get rid of chemicals, industrial pollutants, microbiological contaminants, salts and heavy metals.

In cases where a considerable amount of water is sourced from municipal sources, UV-based purifiers are highly recommended. Water from such sources is relatively safer but gathers contaminants in transit to the end user. UV-based water purifiers are recommended to filter municipally sourced water although RO purifiers too can fit the bill.

Most water purifiers in the market are either based on one of the above concepts or are a combination of any two. There are debates around useful water nutrients being filtered in the process of water purification along with harmful ones. The current products are based on reducing the health risks associated with drinking water. The future will definitely witness advancements that will offer apt solutions. Until then, it’s best for consumers to check the main certifications and arrive at their preferred type of purification process depending on the source of water.

Pankaj Jaiminy is Assistant Vice-President (Food, health and cosmetics) – Testing, Certification and Inspection at TUV SUD South Asia