RO Water Purifier vs Gravity Water Purifier Selection Guide

Water RO System vs Gravity Purifier

Water, a precious natural resource, which is very important for the survival of all living beings, flora and fauna on this planet called Earth.

Even the 70% content of human body is made up of water.

But this natural resource is depleting, and at a very fast pace. And the most common reasons for this are :

  • Inefficient use of water for agricultural practices
  • Over exploitation of ground water resources
  • Sewage and drainage disposal in fresh water resources
  • Lack of efficient water management system
  • And of course, people‚Äôs careless state of mind and unawareness

In rural areas, where the water distress is high due to one or many of the aforesaid reasons, there are growing concerns of water borne diseases such as:

  • Cholera
  • Diarrhoea
  • Typhoid
  • Filariasis

In such a condition, it is very important to have access to clean and safe drinking water to ensure good health and metabolism of our body.

And for most of us, the answer for this question lies in RO i.e. Reverse Osmosis system, that is either installed or should be installed at our homes.

Before proceeding further, let me explain what is Osmosis and what is Reverse Osmosis?

Osmosis And Reverse Osmosis (RO)

Osmosis is a naturally occurring process that happens in plants as well as our human body. In osmosis, a weaker saline solution will tend to migrate to a strong saline solution, when separated by a semi-permeable membrane.

Now Reverse Osmosis is completely opposite to this. since we want to do something opposite to its natural process, we would need a pump to do that.

So basically, a RO system forces the high salt concentrated water i.e. tap water of raw water that we feed into the RO system, through a semi permeable membrane, or filters that are installed in its way, to filter out all the impurities in it, and provide us with clean filtered water that is safe for drinking.

Do We Really Need It

I will try to answer this question by citing the practical example.

How do we decide if we actually need a RO system for our drinking water requirements?

Just because our relatives or friends are using it or because we can easily afford it or it is a social status symbol now or the taste of water is not good.

The decision should not be based on anything else, but the TDS content of the water in your area.

What is Water TDS?

TDS (Total Dissolved Solids) in water are some minerals and ions present in the water. While some are beneficial for our body, excess need to be removed.

Drinking Water Tds Chart

TDS Level in parts per million (ppm) Water Quality
Between 50-150 Excellent for drinking
150-250 Good
250-300 Fair
300-500 Poor
Above 1200 Unacceptable

Water TDS can be checked using TDS meter and the decision should be based upon TDS content of the water in your area.

Please remember, TDS value upto 300 is acceptable.

If the TDS value in your area is high, yes you should install a RO system.

But if the TDS value is less than 300, you should not.

Because there are disadvantages of using RO system also. Let me explain :

  • RO system rejects a lot of water.

The lower the TDS of the RO water, the higher is the amount of RO waste water it will produce.

Let me share my personal experience. When I installed RO system at my home, it was rejecting hell lot of water, 3 times water rejected for  1 unit of drinkable safe water.

But, was it really drinkable and safe?

When I checked the RO water TDS, it was 20 PPM.

Remember, TDS value less than 50 PPM is dangerous for bones and health.

Immediately I asked the service person to increase to TDS value to more than 250 PPM but less than 300 PPM. Now the water is safe to drink and it also rejects very low water comparatively.

  • RO system rejects minerals that are necessary for our body.

This is also related to the concept I shared above. The lower the TDS, more minerals will be rejected in the waste water.

How to check Water TDS at home

There are many digital TDS water meters available in the market which can be used to check TDS of water. While buying, you should check its certification and cost also.

RO installation as well as membrane replacement should be decided on the basis of TDS levels in water.

You can refer this video also for detailed guide for TDS water checking and setting its value.

RO Reject Water or Waste Water Uses

Water is really a scarce natural resource now a days and we should not waste it. We should try to use it wherever possible.

While big industries use RO water waste in their own way, we, at home, can also contribute in this by using RO waste in some of the below mentioned applications :

  1. Housekeeping
  2. Gardening
  3. Clothes washing
  4. Toilet cleaning

The list is not exhaustive and varies from person to person.

Price of RO water Purifier

Ro water purifiers are available in market at various price ranges, and it varies from product manufacturers to various filtration methods it employs. You may find KENT RO water purifier offering various products but in high price range of 15000 INR, but some other companies such as Aquaguard maybe offering somewhat similar products at a comparatively lower price range of around 7000 INR. So it is at the user discretion which product he is comfortable with.

Gravity Based Water Purifiers

Now, what if the supply water TDS in your area is good, but the water colour or taste is not good.

There could be a variety of reasons for that. In such cases, Gravity based water purifiers should be installed. There are many options available in the market.

A gravity based water purifier runs without electricity and speed of filtration depends upon the dust content in the water. If the dust content in water is high, it will take more time to filter.

Basically, it consists of three filters :

  1. Sediment Filter
  2. Activated carbon filter
  3. UF membrane

For the efficient use, these filters need timely replacement.   

These are comparatively cheaper than RO water purifiers.

Now, as we decided what we have to buy, Gravity based purifier or RO water purifier.

The next question comes in our mind is which RO water purifier we should buy?

Well, there are many options available in the market to confuse any one of us. But our decision should be based upon following factors :

  • Service and Installation cost

Usually all RO suppliers provide installation and service upto a certain time limit, free of cost. But still, it is better to confirm once before buying a RO water purifier.

  • TDS controller

Now this is something that is missing in most of the RO water purifiers available in the market. And people often do not ask or be told about this because they do not know why it is important.

Please refer to the example I shared above. If the TDS controller is not installed in the RO water purifier, you will not be able to adjust the TDS of the water, whenever required.

At that time, you have to spend extra money to get it installed and that may not be covered under product warranty.

Always buy a RO water purifier with inbuilt TDS controller.

  • Cost

The utmost important factor in buying anything from the market.  The cost may vary according the RO water purifier storage capacity and other inbuilt support functions such as UV membrane, UF membrane, Alkalinity etc. More services you ask for, more you have to pay.

  • Annual maintenance cost

It is the annual cost incurred in the replacement of carbon filters and sediment filters of the RO water purifier. Normally, it is almost same for our purifiers, and vary according to the size of the membrane and filtration capacity.

UV Filter

This is not really a filter but a UV lamp that kills harmful bacteria and virus in the water. It does not remove dissolved solids present in the water. Hence, it is always found after RO membrane as water needs to be relatively pure before being treated by UV.

Sediment Pre Filter

This is generally found outside the main RO unit in a separate encasement. It contains a microfilter or simply a micro spun (usually 5 microns) which removes sediments or dust particles. The time period could range from 3 months to 6 months depending on the quality of water. It also increases the lifespan of the main membrane of the RO water purifier in India.

Activated Carbon Filter

Activated carbon filter purifies the water by removing chlorine and odour from water by trapping organic compounds and other substances.

I hope this article would help you in practical way while buying a water purifier in an intelligent way and you will not only save water, but also waste less.

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