The pros and cons of using an RO water purifier for your home

RO (Reverse Osmosis) has become synonymous with water purification in recent years. RO purifiers have been known to produce water of distilled-water quality, super-sterile, and super safe for consumption. Before we understand the pros and cons of using RO water purifiers, let’s understand the key terms to understand the RO process.

TDS (Total Dissolved Solids)

Primary sources for TDS in receiving waters are agricultural runoff and residential (urban) runoff, and water pollution discharge from industrial or sewage treatment plants. The most common chemical constituents are calcium, sodium, potassium, magnesium, and their phosphates, nitrates, and chlorides. It is measured in ppm (parts per million) or mg/litre.


A solute is a substance that can be dissolved by a solvent to create a solution. A solute can come in many forms. It can be gas, liquid, or solid. The solvent, or substance that dissolves the solute, breaks the solute apart and distributes the solute molecules equally. This creates a homogenous mixture, or solution that is equal throughout. In the context of an RO purifier, the Total Dissolved Solids make up the solute part of a solution.


A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. In the context of an RO purifier, the solvent is the water in which the total dissolved solids are dissolved


A solution is a special type of homogeneous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent. In the context of an RO purifier, a solution is nothing but the water supply from your tap water that becomes the feed for the RO purifier unit.


Solutes in solution are measured by their concentration. The concentration of a solute is the amount of solute divided by the total volume of solution. A solvent can dilute various amounts of solute, depending on how strong of a solvent is used and how easily the solute molecules come apart. This property of solutes to dissolve in a solvent is known as solubility.


Osmosis is a naturally occurring phenomenon where the solvent moves from a medium with low solute concentration to a medium with high solute concentration through a semi-permeable membrane. This is the natural tendency of any solvent.

Reverse Osmosis

In Reverse Osmosis, the pressure is applied on the semi-permeable membrane in such a way that it overcomes the natural tendency of osmosis and makes the solvent move from a medium of higher concentration to a medium of lower concentration through the semi-permeable membrane. The semi-permeable membrane in the RO purifier is the RO membrane that contains pores whose diameter is 0.001 microns, which prevents the passage of particles larger than that size. Typically, in terms of weight, the Reverse Osmosis doesn’t allow particles with a molecular weight greater than 200 to pass through.

Let’s now look at the pros of using an RO purifier at your home

The pros of using an RO purifier

  • Reverse Osmosis produces water that is clean, pure, and safe for consumption. It eliminates up to 95% of TDS (Total Dissolved Solids), not only turning hard water into soft water but also purifying it. If your TDS meter shows that your TDS is anything above 500 ppm, getting an RO purifier is a no-brainer.
  • An ultraviolet purifier uses a UV lamp to deactivate the core of microbes. However, using only a UV purifier would mean that you would still end up drinking remnants of these deactivated microbes. Reverse Osmosis is one step ahead of Ultraviolet purification as it removes the microbial remnants from the water. Usually, RO is combined with UV for the best results.
  • RO purified water is also free from foul odor and taste as the contributing chlorine and Fluorine compounds are filtered by the RO membrane. Other than this, RO prevents waterborne diseases and the accumulation of heavy metals ions in your body.
  • Modern RO purifiers are fully automated from how they are engineered to how the unit alerts the consumers when the UV lamp goes off or the membrane needs replacement or if service is due.
  • RO units are compact, easy to maintain, and clean. The only cost you incur over the lifetime of the water purifier is the RO membrane (recommended that you change at least once in a year) and any mineralizer cartridges.

Please do check the complete range of RO water purifiers from Pureit once you decide to purchase an RO water purifier.

The cons of RO water filter

  • RO water is near sterile as more than 95% of TDS is eliminated by the purifier. This means the water is tasteless, which can be countered by using a purifier with a TDS modulator or a mineralization cartridge.
  • The quality of RO purification hinges on the quality of the semipermeable RO membrane. The consumer should be alert to the possibility of chlorine compounds clogging the pores which would result in a drastic slowing down of the RO process. It is therefore recommended that you purchase a RO purifier that uses pretreatment filters like sediment filter and active carbon filter that filter the chlorine and fluorine compounds and hence prevent the damage caused to the RO membrane.
  • It is also possible that bacteria and other pathogens accumulate on the RO membrane which could ironically become their breeding ground and affect the quality of filtered water. It is recommended that you purchase an RO purifier from a reputed brand that has service personnel to attend to the maintenance needs.
  • RO is costlier than gravity-based purification systems, but in the end, remember that health is wealth. Nothing is more important than a reliable water supply free from contaminants.
  • RO wastes water. There is water wastage involved in the RO process but here is the good news. The drained water from the reject water stream can be repurposed for cleaning, gardening, etc., so it is not totally a waste. Also, keep abreast of the advances in technology – like Eco-Saver technology from Pureit – which can reduce water wastage by a whopping 65%.

Read on for a more comprehensive guide on why you need a RO water filter.