Clean and safe drinking water is not a luxury—something one wants—it is a necessity. As pollution, industrial waste, and water-borne illnesses are on the rise, traditional filtration methods like boiling or filtering with cloth are not sufficient anymore. This is where fresh water purifiers like RO (Reverse Osmosis) water purifiers are coming to our rescue.
What Is an RO Water Purifier?
RO (Reverse Osmosis) water purifiers are high-end filtration systems that remove dissolved contaminants, toxic chemicals, heavy metals, salts, and bacteria from water to yield pure, clean, and taste-perfect water.
The secret of the RO system lies in a semi-permeable membrane through which only water molecules are able to pass and reject the majority of other impurities. It is pressurized and is particularly effective at cleaning hard or high-TDS (Total Dissolved Solids) water.
RO purifiers are particularly suited for:
• Houses having borewell, tanker, or groundwater supply
• High TDS or metallic contaminated regions
• For protection against waterborne diseases
Why Do You Need an RO Water Purifier?
You may ask yourself: isn’t tap water treated by the local municipality?
Though most cities supply treated water, it’s not always pure by the time it reaches your home. Pipes are corroded and old, groundwater is polluted, and storage tanks aren’t cleaned regularly. RO purifiers provide the additional safeguard by:
• Removing excess fluoride, arsenic, lead, mercury
• Eliminating bacteria, viruses, and cysts
• Neutralling unpleasant taste and smell caused by chlorine or sulfur
• Serving clean, mineral-balanced water for drinking and cooking
How Does an RO Water Purifier Work?
A standard RO purifier has multiple stages of filtration, sometimes with RO and UV, UF, carbon filters, etc. Below is a step-by-step breakdown of how water flows through the system:
1. Sediment Filter (Pre-Filter)
The process starts with a sediment filter that eliminates visible contaminants like:
• Dust
• Sand
• Rust
• Mud particles
This shields the RO membrane from abrasion or clogging, adding life.
2. Activated Carbon Filter (Pre-Carbon)
Secondly, water is filtered through an activated carbon filter, which removes:
• Chlorine (which damages the RO membrane)
• Pesticides and organic chemicals
• Bad taste and odour substances
This process improves the taste and safety of the water.
3. Reverse Osmosis Membrane (Core Stage)
This is the purifier’s core. Here:
Water is filtered through high-pressure semi-permeable RO membrane.
There are microscopic pores (about 0.0001 microns) in the membrane.
Water molecules are filtered individually, while contaminants such as:
• Dissolved salts (TDS)
• Heavy metals (lead, arsenic, etc.)
• Nitrates
• Microbes
are eliminated and released as wastewater.
up to 95–99% of all dissolved harmful substances are eliminated in this process.
4. Post Carbon Filter (Taste Enhancer)
After RO treatment, the water would lose very little of its original taste because minerals have been removed from it. The post-carbon filter benefits by:
• Enhance taste and freshness
• Eliminate any lingering odour or gases
• Make the water fresh and edible
Other models also have a mineralizer to replace vital minerals such as calcium and magnesium.
5. UV Chamber (Optional but Highly Recommended)
To provide additional protection, some RO systems have a UV sterilization stage, where:
Water is treated with ultraviolet light, which kills the DNA of any surviving bacteria or viruses.
It’s chemical-free and quick disinfection.
This makes it biologically safe water even in instances of extreme microbial contamination.
6. UF (Ultra Filtration) Stage (Optional)
Water, in certain RO+UF systems, is filtered through an ultra-filtration membrane with pores just slightly larger than RO. This operation serves to:
• Catches bacteria, cysts, and sediments
• Delivers clean water even without electricity
UF proves especially useful in regions of low quality of water or irregular power supply.
7. Storage Tank and Dispenser
Lastly, the filtered water is stored in a sanitary tank, usually between 7 and 10 liters in capacity. The dispenser makes it easy for you to pull water, similar to a faucet or water cooler.
Some of them also have smart features like:
• Filter change alerts
• Water level indicators
• Auto switch-off when the tank is full
How Much Water Is Wasted in RO?
One of the most common grievances against RO systems is wastage creation. On average:
2–3 liters of water is wasted for every 1 liter of purified water.
This reject water, however, can be utilized in:
• Mopping floors
• Washing cars
• Watering plants (if TDS is less than 1200 ppm)
New-generation models incorporate water-saving technology and TDS recovery systems in order to minimize wastage.
Pros and Cons of RO Water Purifiers
Advantages
• Removes 99% of impurities
• Enhances flavour and aroma
• Uses safe drinking water and for cooking
• UV, UF, and mineralizer can be customized
• Hard water regions compatible
Disadvantages
• Saves very little water
• Needs power to operate
• Removes some beneficial minerals (can be replenished with a mineral cartridge)
• Needs periodic maintenance and replacing of filters
RO Purifier Maintenance Tips
To ensure consistent performance:
• Replace pre-filters every 6–12 months
• Replace RO membrane every 12–18 months
• Service UV lamp (if equipped) every year
• Clean storage tank periodically
Neglect of maintenance may result in system failure and poor quality water.