When it comes to health and safety, quality of drinking water is highly important. Contaminated drinking water is a continuous source of health hazard and needs remedial actions to be taken on an urgent basis. The importance of safe water and its relationship with health is widely known.  Water should be safe for drinking, cooking and hygiene. According to the guidelines of WHO, water should be safe to consume in terms of the following four aspects.

Microbial aspects

This means that drinking water should be free of bio-invaders. Consumption of drinking water contaminated with disease causing germs is highly fatal in the long run. Children and people in the old ages are more susceptible as their immunity is not fully developed. It has got immense importance and compromises cannot be made in managing the microbial exposure in drinking water. Many local municipalities strive to disinfect such water and chlorine is highly consumed for disinfection of drinking water.

Chemical aspects

Presence of certain chemicals in the drinking water raise serious health concerns. These chemicals make sometimes water undrinkable due to bad odor, a peculiar taste and affect the overall appearance. Though some chemicals act as a barrier against certain diseases such as fluoride provide prevention against dental cavities and is added in supply line by municipalities itself. Chemicals in drinking water at an acceptable level are not alarming as much as they do not cause health impairment.

Radiological aspects

Radionuclides sometimes are naturally present in drinking water. Water should be save from radioactive materials in case they pose a threat to health. Risk mitigation must be ensured if radionuclides are present in water up to a dangerous level. Approach should be preventive whenever allocation of resources is done for drinking water safety.

Acceptability aspects

WHO tells that the water should be acceptable to drink by the individuals in terms of its appearance. No one would like to drink a muddy and cloudy water. Secondly acceptability also means that it should not be having an unacceptable taste and bad odour. Otherwise it will affect the hydration in the long run.  If microbial, chemical and physical aspects are not taken into consideration with respect to safety then acceptability will automatically get influenced. All other three contaminations are likely to affect the appearance of water.

RO Water Filter Systems Vs Other Water Purification Methods

There are many water purification methods other than traditional method of boiling in the marketplace. Reverse osmosis water filter systems are highly in demand as compared to other filtration techniques due to their immense effectiveness.

RO (Reverse Osmosis) Water Filter Systems

Purification Method

The most common and popular purification systems nowadays are reverse osmosis water filters systems. Reverse osmosis is abbreviated as RO. RO water filter systems work on the basis of osmosis a naturally occurring phenomenon. Osmosis refers to the movement of a solvent that is lower in solute concentration towards the solvent of a higher solute concentration when they are separated from each other through a semi permeable membrane. A semi permeable membrane is a membrane that do not let everything to pass through it. This tendency of the solvent molecules is known as osmosis. In other words, it can be said that water flows from its high potential where there is less solute towards its lower potential that has more solute dissolved until both water diffuses. This movement keeps on going until both solvents achieve an equilibrium. This property of water is used in reverse osmosis water filter systems in exactly opposite way. In RO water filter systems impure water is pushed by a water pump through a reverse osmosis membrane. RO membrane filters the impurities in the water up to 0.0001micron which is just a semi-permeable membrane.  For once, RO membrane removes completely everything from the water.



RO water filter systems usually houses different filtration stages to make drinking water pure and safe. These systems use a combination of different purification methods. Sediment filtration and UDF filtration are utilized as initial filtration techniques before water passes through reverse osmosis membrane. In addition, RO water filter systems have been designed for many post filtration water treatments. In the first step in very basic RO water filter systems, water passes through polypropylene cartridge that purifies impure water from all types of suspended particles such as sand, clay and silt. The main purpose of this sediment filter is to protect the reverse osmosis membrane as well as whole filter from any clogging due to presence of solid suspended particles. This pre-filtration membrane removes impurities in the water up to 5 µ. In the second step, granular activated carbon and carbon block filters remove the bad taste and odor in the water caused by chlorine and chloramines. Together these two carbon cartridges increase the performance and efficiency of each other and block many VOCS, pesticides and inorganic compounds along with chlorine.

Reverse osmosis membrane filtration

Pre-filtered water is passed through then reverse osmosis membrane on the principle where a solvent (impure water) is passed from an area of higher concentration to low concentration of impurities. This removes all remaining impurities from the water that still exist after pre-filtration. Once the membrane removes completely everything from the water, the water even gets void even of essential minerals. The water at this stage is not fit for drinking purposes as it lacks even essential minerals which are required for proper functioning of the body. Many advanced reverse osmosis systems have post treatments as well in order to remineralizer water.

Post Filtration

In the post treatment, a mineralization tube enriches the water with the required minerals by adding back the desired level of minerals and nutrients. Another post feature is taste and odour tube that readjusts the taste of the water making it a desirable one. Advanced systems have more features added such as the adjustment of pH to provide you with an alkaline water. This stage softens the water and remove the acidic nature of the water. We all know that the best water for the body to assimilate all the essential nutrients from the food is the alkaline water. Another post feature is an antioxidant filter that sterilizes the water completely. Especially after Covid, this system is highly desirable as it contains an anti-microbial filter which removes 99% of the bacteria and germs from the water making it safe and pure to drink. Some RO water filter systems use ultraviolet sterilization as well.


  • Ideal for drinking water purpose
  • Best under the sink placement filter
  • Filters water up to 0.0001 micron
  • Filter cartridges are easy to maintain
  • Multiple Stages of Filtration
  • Nourishment and retention of water with mineralization tube
  • Odorless water and taste as per your choice
  • Alkaline water pH ideal for body functioning
  • Anti-microbial removes 99.99 % disease causing organism
  • Reverse osmosis membrane has a longer life


  • Takes more time to install
  • Needs electricity for operation
  • Wastage of water due to backwash
  • Need storage tank due to slow filtration rate
  • RO water filter systems need mineralization tube for full effectiveness otherwise you will be putting your family's health at risk

Other purification methods

Carbon Media

Another popular method of purification is based on carbon as a filtration media. Carbon based filters perform purification usually in two forms one is granular activated carbon media known as GAC and the other is carbon block. Granular Activated Carbon Cartridges are made from acid washed coconut shells and coal with high concentration of carbon whereas carbon block filter cartridge is made by compressing the loose carbon into a solid compact structure which enhances its capability to absorb impurities massively. Carbon media removes bad odour and taste from the water improving the acceptability aspect of water. Together they make water void of several chemicals, specifically Volatile Organic Compounds (VOCs), pesticides, hydrogen sulfide, nitrates, heavy metals and many others etc.


  • Best for cooking, and dishwashing
  • Ideal for caffes and coffe shops
  • Placement is under the sink
  • Filters water upto 0.3 to 0.01 micron
  • Perform ultra-depth filtration
  • Easy to maintain filter cartridges
  • Takes less time and space to install as compared with RO water filter systems
  • No need for electricity
  • No water wastage
  • Consistent water supply with no need for storage
  • Removal of chlorine and chloramines


  • Not very ideal for drinking water purpose
  • No protection against bio-invaders such as bacteria and viruses
  • No adjustment for pH

KDF Media

KDF media is another form of water purification that is mainly used in shower filters. This media is made up of cooper and zinc granules that use oxidation reduction reaction. This medium removes chlorine, heavy metals, hydrogen sulphide and some bacteria. It has got different variations that are productive for removing different impurities.


  • It is less expensive
  • Inhibits bacterial and fungal growth
  • Easy to install without taking much time


  • Works effectively in a combined arrangement with other filtration techniques
  • Requires backwashing
  • Do not remove some organic compounds
  • Pesticides and herbicides are not removed

Ion Exchange

Ion exchange method involves the use of resins in the form of beads that attach to the hard ions present in the water. This method is mainly used in water softeners. Ion exchange method tends to replace the hard ions in the water make it softer by replacing it with positive and negative charged ions present in the form of beads. Hard minerals such as magnesium and calcium along with other toxic materials and heavy metals are removed by utilizing these resin beads. 

In water softening process, swapping of ions take place where negatively charged sodium ions present in resins bound to positive ions of calcium and magnesium. Calcium and magnesium usually gets converted into less dangerous salts and are backwashed from the water. Ion exchange technology prevents lime scale build up and hence protects appliances such as washing machine and dishwashers.


  • No hard water in the whole house
  • Silky hair and glowing skin
  • Soft vibrant clothes
  • Usually gets installed at the Point of Entry
  • Your silverware and glassware are cleaner and shinier.
  • Time on cleaning is saved


  • Can't be used alone need some pre-filters
  • Alone not fit for drinking water filtration purpose
  • Needs time for installation
  • No protection from microbial perspective

Ultraviolet sterilization

Treating drinking water with ultraviolet rays is another form of water purification. This method uses a UV light emitting lamp in order to get rid of bacteria and viruses. The lamp is very effective in water sterilization from many disease-causing germs. The UV rays destroy the protein coating of germs and hence limit their ability to multiply. But without the presence of other filters such as carbon and sediment filters it is not of much usage because a specific odour and taste will still be there. Many other unnecessary and harmful chemicals cannot be removed alone with a UV steriliser. Many anti-microbial filters exist in the market as a replacement of UV filters as they have got more complaints.


  • Remove germs and harmful microorganisms from water
  • Good for immunity and health


  • Need electricity in order to perfrom
  • Uanble to remove sediment, rust, dust and other chemicals when used laone
  • Require some other filters for effective filtration
  • UV lamp is expensive
  • Need replacement yearly

Sum up

Different filtration methods have got different pros and cons. Many of them are used in combination to get desired benefits. The above discussion has been intended to clarify the difference between various methods of water purification. Every method targets different impurities and each one has been designed to cater different needs according to the budget. It doesn't matter which method you choose for water purification but purity and safety of drinking water is very pertinent to health. Safe and pure water is health. Hydration gets affected if water is impure and appearance is bad in looks. Clean drinking water helps us in building immunity. It also brings improvement in the taste and aroma of food and prevents skin from allergies. As per municipality tap water is safe to consume but health is wealth so purified water is always more beneficial for the health and well-being than impure water.