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Selection of a Domestic RO System - How To? - Delhi

Dear Experts,

I reside in South Delhi (Malviya Nagar). Up till now I relied on bottled water for drinking and cooking. Currently I would like to opt for a more permanent solution like a domestic RO system.
My problem is my limited experience and would like to seek expert knowledge on the system.

To select the best and advanced system for my household what do I need to know
(a) about my water supply and water quality?
(b) Do I need to test my current water supply or merely pick a brand?
(c) What definite advantages are there between seven stage systems & RO+UF+UV+TDS control?
(d) Is it all about source water or the selection of a correct brand?

Kindly help me resolve this problem.





1. Dear Vineet,First of all,

Dear Vineet,

First of all, select your raw water source. Is it borewell or a government supply? You need RO only if you have a higher TDS Say above 250-300 mg/litre.

For Govt. Supply - You select UF membrane based domestic system, which won't alter the TDS but would take care of other impurities.

For Bore water - Go for RO based system with blending by UF. This will give you an purest water blended by UF. Do not go with only RO as it will give almost desalinated water with a low pH. [Acidic].

Tushar Trivedi
Bottled Water Segment
Bottled Water India
New Delhi

2. Dear Vineet, 1. I would

Dear Vineet,

1. I would suggest you should first get a sample of you water tested at a reputed lab. (If you want you can scan and mail the test report and I will give you my expert opinion on the report).
2. Call on 3 or 4 of the most 'visible' manufacturers of RO purifiers to come and give a home demo of their products. On such occassions they will also test the TDS (total dissolved solids) of the water available at home. If you have received the Test report from the lab, compare the TDS in the report with the figure the sales person tested with his TDS meter and see which is lower.
Ideally, a TDS of 1200ppm is the maximum safe level to use an RO.Anything higher, say 1500ppm and more means trouble.
3 Several stages of treatment is an indication that everything does not depend on a single treatment stage.About " TDS control", I don't think it is necessary. It is more of a sales gimmick.
4 It is all about the water and also the quality of service each of the companies can give after selling it to him. I suggest you should ask others who have ROs at home.
Finally, I would caution you that an RO is quite wasteful. If an RO is fed with water to be treated, approximately 10 to 20% of what is fed will be treated and rest has to go to waste. It is a feature of all RO systems and no one claim that theirs is different.


Water Management Consultant
Ion Exchange

3. Dear Vineet, You may kindly

Dear Vineet,

You may kindly see BIS 10500 for drinking water standard.  It is also for information that there are statutory rules/regulations e.g. Water Pollution Control Act 1974, Environment Protection Act 1986, Bio-medical Waste (Management and Handling) Rule 1998 etc which can take care of very many pollutants.
But what is most needed in the country is environmental discipline.


Dr. Arunabha Majumder
Chairman, Indian Water Works Association (IWWA) and Ex-Director-Professor & Head, Department of Sanitary Engineering, AIIH&PH, Kolkata and  Guest Lecturer, School of Water Resources Engg., J.U.



4. Dear Mr. Vineet, For drinking

Dear Mr. Vineet,
For drinking water two things are important- first is safety and another is taste. For safe drinking water –disinfectant process should be clearly known to purchaser. You can kill all bacteria by chlorination, ultra violet rays or by reverse osmosis. Reverse osmosis rejects all particles more than 1 micron. Stages in RO water treatment are for protection of membrane against fouling.

Taste of drinking water depends on mainly TDS and volatile matters present in water. Volatile matters are trapped in carbon filter. TDS is controlled thru RO membrane.

1)      Just check two parameters in incoming water- total dissolved solids and turbidity.
2)      TDS less than 200- go for UF with carbon filter+UV, TDS  200-600 go for RO with TDS controller, TDS more than 600- go for any brand without TDS controller.
3)      If turbidity is more than 5 NTU, please install bigger size (2 nos) pre filter.
4)      Source of water is more important than brand.

A.K. Singla
Engineer (Utilities)
Panipat Refinery

5. Dear Friend, (a) About my

Dear Friend,
(a) About my water supply and water quality?
Reply: RO shall be selected on the basis of TDS for domestic application. You may select a domestic RO on the basis of TDS of water from a reliable supplier.
(b) Do I need to test my current water supply or merely pick a brand?
Reply: It is best to check the water quality before buying a system. Normally, domestic RO suppliers have a hand held pen type TDS meter which is not very accurate but reasonably reliable for the same. They shall check the TDS and inform you of the best suited unit.
(c) What definite advantages are there between seven stage systems & RO+UF+UV+TDS control?
Reply: The steps you mentioned are already part of the 7 stage system. Micorn filter, UV, ACF, RO, TDS control are the terms which form part of the 7 stages. TDS control is nothing but throttling the outlet of reject to ensure more treated water out of system of slightly higher TDS. You may go for RO on basis of your water quality.
(d) Is it all about source water or the selection of a correct brand?
Reply: It is always about the source water and never about the brand. Brands may not be the right way of going about it. It is like some doctors are better at diagnosing symptoms than the best known or acknowledged doctors (read brands). It is always about the diagnosis of the illness and never about the doctor. A good doctor shall always read the symptoms right whether he/she is famous or not. Likewise for water treatment. Hope you got the point.
Taral Kumar
Executive Director
Akar Impex Pvt. Ltd.
Noida, Uttar Pradesh

6. What is the acceptable TDS for drinking water


I recently got the TDS level of water checked from the RO system installed in my house. It came out to be 17-20 ppm, i wanted to know is this TDS level safe for drinking? The input TDS level is approximately 400 ppm.



7. All About TDS

Dear Deepak,

You can learn all about acceptable TDS levels here:

Thank you,
India Water Portal Team

8. Please help me select RO system

Water TDS level at our home is above 1600. I need suggestions to get long lasting water purification system. Please name specific brands or models.

Thank you

9. TDS found to be between 12-14 from RO purifier - Is it safe?

I have a RO system at my home. Upon checking TDS using a meter, we found that the values were between 12 and 14. Is it suitable for drinking ?

10. You should consider using an electronic water conditioner

You should consider using an electronic water conditioner after boring the pump and before you consider RO or water filters. This will give you the following benefits:

1. All the germs and bacteria in the water will get killed.
2. Scale forming calcium carbonates will get eliminated

The net result is :
1. Longer life for the water filter.
2. Less maintenance on the RO plant
3. No scale formation on your taps, water heaters , solar water heaters.
4. No corrosion on pipelines

Contact me , in case you need more information.
Vikram Dandekar

11. Need info of water testing labs in Madurai, Tamil Nadu


Recently I noticed scale formation in the pipelines at home in Madurai.

Need information on water testing labs in the area to test water from my borewell and find the suitable domestic water purification system.


12. What is water conditioning?


What is water conditioning?

13. IS UV+UF+RO+TDS safe?

I havn't got the TDS level of water checked. If I install a system like kent which has UV+UF+RO+TDS. Can it cause an harm?

14. Which is the best place to get water tested in Delhi?


We have a centralized R.O. installed in our society, but the pipelines are pretty old, so the tap water is unfit for drinking. We thought of getting the pipeline changed, but we can change only a part of it and contamination would still be there. Hence we're planning to go for a purification system.

Can anyone tell me if there are any labs (in Dwarka/Delhi) that can get the water sample collected from home, and send us the reports?
Thanks in advance.

Ashu Nitin Anant

15. Water testing labs in Delhi


Here's some information about where to get your water tested in Delhi.

1.Min Mec R&D Laboratory New Delhi

2. Spectro Analytical Labs Ltd
E-41 Okhla Ind Area Phase-I1,
New Delhi-110020
Phone: 011 40522000, 41611000

3. Development Alternatives
111/9-Z, Kishangarh Vasant Kunj
New Delhi - 110070
Tel: 91 (11) 2613-4103, 2689-0380
Fax: 91 (11) 2613-0817

4. Water, Air, Chemicals, Food, Oil Analysis at
Gurgaon & Delhi
Mobile: 9810098791

5. Delhi Test House
A 62/3 G.T.Karnal Road,
Azadpur, Delhi - 33
Tel: +91-11-47075555 (30 lines)
Fax: +91-11-47075550

Apart from this, the Department of Drinking Water and Sanitation under the Government of India hosts a query for finding the nearest water quality lab for any taluk/block in the country.
You could access it here:

Hope this helps.

Seetha Gopalakrishnan
India Water Portal Team

16. All questions answered - Link to a very good article

You can find all your answers to the best of your satisfaction in this well researched article at the following link:

17. Should I buy a RO or a regular purifier?

I live in Gautam Nagar.  A representative from Kent RO came and tested the water for me and said the bore water is 250 and govt supply water is 122 and that I need to change water system in my house. Suggest what should I do, I have 2 small kids in my house. Should I go for Ro purifier or a regular purifier will do. Also any suggestion on some good companies

18. Info on filter to use for water going to overhead tank

Kindly let me know the system I should use to filter the water going into my overhead tank. I find red worms and back sediment every month on cleaning my tank. I use a reverse osmosis filter in my kitchen but what about the rest of the house. Very grateful if someone could help me out.

19. Would like to know which water filtration is better RO or UV

I have a Aquaguard classic UV water filtration unit installed in my house, where we get water from public water supply system. I have not tested TDS level of the water or other factors.

I have been advised that I should go for a RO system as the normal UV unit I have is worthless. Please guide me.

20. Calibration, verification & suitability tests water quality

The choice between a millinery single, field verification procedure, a complete calibration procedure, or more specifically USP suitability tests is made depending on the impact of water on your applications and on the type of accreditation or quality management system that has to be followed.

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