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Minimum TDS Level : Setting TDS Levels on RO Systems

Recently as a salesman was giving a demo on a RO system, he told that the TDS level will be reduced to 10. Is it a safe TDS level or all the minerals will be removed if it is very low. But i read somewhere that the ideal mineral water should have a TDS level atleast of 150. What should be the minimum TDS level for the drinking water and what should be the maximum? Will the RO systems allow us to set the required TDS level?? If so what should be the thumb rule used to set the same?




51. Is UV tube & TDS adjusting valve necessary?What is optimum TDS?

We live in a 10 storey building and we get drinking water from the overhead tank. The builder has provided a RO system (the specifications of which are not known). Recently we got the filter candle changed. At this time the service man checked the TDS which is only 7. We got the water which did not pass through the RO System and it was 350.

The service man has advised us to attach a UV tube and TDS adjusting valve. Is it necessary? What should be the optimum level of TDS? What should we do?

52. TDS in your RO is to low and not advisable, it is of very less

Dear Dipak,
Your service man is right. You should attach an UV tube and a TDS adjusting valve, because generally the normal TDS level suggested for us is 150 to 500. The TDS in your RO is to low and not advisable, it is of very less. As a human we require some minerals, salts as per our body need, now the TDS adjusting valve will help u to maintain TDS. It also change your water taste also.

Sunil Barot
ORG: Eng.Tech.RO system
Gandhinagar, Gujarat 9909903847

53. There is absolutely no need for RO treatment

Dear Mr.Naik

If your feed water has TDS of only 350, why do you even need to do a RO on it and reduce the TDS to 4? Water with 350 TDS will taste better than water with TDS 4. The presence of some salts in the water actually makes water more palatable.

Indukanth Ragade (

54. The upper limit of the BIS standards for drinking water is 2000

Dear Mr. Sanjeeva Kumar

Can you give literature reference to the so-called specialists who say that ideal drinking water should have TDS 50 or less? This is totally wrong.

You also mention that drinking water with TDS more than 1000 is harmful? Can you give the basis on which you make this statement? The upper limit of the BIS standards for drinking water is 2000 and they do not mention anything about this water being harmful.

Indukanth Ragade (

55. Few corrections in some of my previous comments

In my response to the problem raised under this query and on some of the comments on it, I had sent my own comments on March 12th. Unfortunately, there are a few slips in it.

In the first para, the reference to Sagtata Mazumdar should actually be to Dharma on his mail of Feb 20th.

The second para refers to Sugata Mazumdar and some others with connected problems.

Indukanth Ragade

56. Is it safe to drink water with 832 TDS?

A sales person from a top purifier company checked the water level in my house and told me that the tap water (regular salt water) is giving a TDS count of 832 and the filter water (we generally buy in can) is having TDS of 16.  

He said that the TDS as per WHO should be 50 to 200 only anything above or less is bad for health.  Considering my son who is 3 years of age, I request for your suggestion and help on this.

57. Need to be more concerned with pollutants

With regard to drinking water, the more important consideration is pollutants in the drinking water.

Reducing TDS is fine if you have hard water from a well, but whether your water comes from a well or through a municipal water supply system, you need to be more concerned with organic and inorganic pollutants like arsenic, chromium, iron, fecal  and bacterial matter and so on. It's the safety of the water which should be of primary concern.

In my town, the water supplied by the water board is unsafe to drink because of various pollutants, either not being removed during treatment (if at all the water is treated) and/or being polluted along the way due to defective/broken pipes in the supply line. I boiled off 80% of a sample of water, and was left with something that looked very much like dark urine, so I installed a multi-stage purifier including R/O, although my TDS was only about 200ppm (it is now about 40ppm, and tastes the same as leading bottled water). Now the water passes my boil test too.

The WHO white paper on drinking-water quality can be found here:

58. Is a TDS of 60 in RO system drinking water safe?

Recently I purchased the 'Ever Sure' RO system water purifier. In this system, water TDS shows 50 to 60. Is it safe to health?

What is the TDS limit for good drinking water?

Thank you

59. What is the drinking water TDS level fit for consumption ?

Dear sir,

We had a fixed RO system. Its TDS level is 120-150 after RO purification. Earlier our direct bore water TDS is 65o only. What is the TDS for good drinking water ?

60. TDS level of 100-300 is good for drinking purpose

TDS level of 100-300 is better for drinking but 150 is the limit according to Indian standard and 70 according to standards abroad.

61. TDS level of 100-300 is good for drinking purposes

Dear Arvind Singh,

The Indian Standard set by the Bureau of Indian Standards which is one we should use as a reference states something totally different. The standards very clearly states that potable water should ideally have TDS upto 500 and also says in the absence of this quality, water having upto 2000 TDS can be consumed.

Indukanth Ragade

62. TDS is at correct level

Dear Hari,
It is the perfect level. I am sure you must me having very good taste of water at this level.

63. Contact BLUCOL advanced RO systems

Hello readers,

If you want to know more about your drinking water please call us on 1800-1200-143 (toll free) or 09813028643

Mr. Rakesh Vats (PhD in water solutions)

64. Rakesh, We can meet at a mutually convinient date & time

Thanks Rakesh,

Let us know know your contact address in Pune, so that we can meet at a mutually convinient date & time

Sincerely, Vilas B Joshi, for Niwas Enterprises Pune

65. What is the standard level of TDS?

Dear Sir,

I am using well water for drinking having and it is found to have 179ppm TDS. Kindly suggest me if it is safe for drinking or not.

A sales person from well known brand told me that the TDS level should be under 50 ppm. Please help me for the right TDS level.



66. Previous responses from IWP users

Hi Yogesh,

These are some of the responses from our users in the past. Please go through them. Hope you find it useful.

And if you have time, you could also go through this write up on TDS

Seetha Gopalakrishnan
India Water Portal Team

67. Should I install RO or UV water purifier?

Recently I've given the sample of municipal water to a shopkeeper and he'checked it and informed us that our drinking water has a TDS of 367. So kindly suggest whether we should install only Reverse Osmosis (RO) water purifier or RO+UV?

I am confused, as I cant decide on what basis we have to install water purifier at home. It should be safe for drinking.

Awaiting your reply.

68. UV filters are not harmful

RO is not acquired at all! UV is not necessary but not harmful, it will kill the bacteria in the water with almost 99%

69. TDS is ideal for drinking in your water

Dear Gagan

Please see the section on Minimum TDS levels - Setting TDS levels on RO, you will get plenty of information.

Briefly, the TDS in your water sample is within 500 which is ideal for drinking as far as salt content is concerned. So no RO is required. The best course is to boil this water, cool it and drink it.

Indukanth Ragade (

70. Should I go for RO? TDS is 432

I have a TDS of 432 in my drinking water and the salesman is insisting that I purchase RO. Should I take it or not? What should be the right amount of TDS in water?

Awaiting you reply.

Pratibha Verma

71. Should I use RO or UV, TDS level is 108 in drinking water

The ideal limit of TDS for drinking water is 500 and yours is 432. Don't go anywhere near RO and get fooled and waste money.

Indukanth Ragade

72. Want to know about literature available on testing


I want to know about the literature available on testing of different water parameters. Please share with me the names of books and authors name of it

73. TDS of drinking water

What is the TDS for drinking water? Please let me know.

74. Please refer the manual on water supply & treatment

Please refer the manual on water supply and treatment published by the Ministry of Urban Development - Third edition Revised and updated, May 1999

Recommended guide line values for Physical and chemical parameters: Table 2.2 ( 14-16) TDS (mg/l) acceptable value is 500 and cause for rejection is 2000

For access to the manual -

M.Sankaranarayanan,  Rtd Joint Adviser (PHEE) CPHEEO

75. Changing of RO filter - After how long should it be done?

I have purchased a RO system of Aquafresh company. I want to know, after how many days/liters used should the system's filters be changed?

76. Should I stick to my old UV filter or retain the present RO one?

At our place, the water that is supplied has a TDS of 428. I checked the water from a reputed bottling company and it shows a TDS of 180. My RO shows 34.

The serviceman has added a valve to add some of pre-filtered water in RO tank to increase the TDS to 140, but the taste of water is not good.

Kindly suggest whether I should install my old UV filter and remove this RO or keep this new one.


77. Is it good to drink water with such low TDS of 10-12?

Hi everyone,

I am staying in Dehradun and the TDS level is 375 as per the sales executive of Aquaguard who came to my house for installation of RO. Since this place is contaminated with high percentage of Calcium, now my RO shows TDS of 10-12. Is it good to drink water with such low TDS? Please answer.


78. TDS level for RO filtered water

What is the ideal TDS level for RO filtered water?

79. Want to know the TDS level in kent (RO+UV+UF+TDS) water purifier

At my home the TDS level is 700. I have purchased kent (RO+UV+UF+TDS) water purifier. The sales executive of Kent modified the TDS level to 25.

I want to know if this is good for health?

Please let me know.


80. Want to know the TDS level in Kent (RO+UV+UF+TDS) water purifier


In my house the TDS level of the water is 700. I have purchased Kent (RO+UV+UF+TDS)water purifier. The sales executive of Kent adjusted the TDS level to  25. I want to know if that it is good for health.


81. Should I install RO purifier when there is already a softener?

I am moving into my new apartment which is providing water treated with water softener plant. Do I have to install a RO water purifier?

82. If your water has less than 2000 ppm, there is no need for RO

Dear Sajana

A softener reduces the quantity of certain salts which will react with soap and result in reduced foaming and warrant increased usage of soap. On the other hand, an RO system is needed only when the dissolved salt content in the water is more. The ideal content is below 500 parts in a million parts of water (PPM) and the compromise is upto 2000 parts. If your water is having less than 2000 ppm, there is no need for any RO.

Indukanth Ragade

83. Want to know the TDS level in Kent (RO+UV+UF+TDS) water purifier

Dear Shweta,

Water with only 700 TDS can be consumed and also used for cooking without any treatmetnt. There is no harm in drinking water with TDS 75 but it may not taste as good as drinking the untreated water.

Indukanth Ragade

84. TDS in RO water, can we go to consumer court against Kent RO?

For TDS in RO water, can we go to consumer court against Kent RO, as they have sold us RO forcefully telling that TDS should be as low as 4-7 in water, otherwise dangerous for health, while our tap water was giving 150 TDS.

Please reply.

85. Consumer Protection Act, 1986

Dear Jasneet,

I looked up at the The Consumer Protection Act, 1986 (Bare Act), I came across this. This comes under the definition for complaint:
(c)  "complaint" means any allegation in writing made by a complain­ant that—
(vi)  makes a false or misleading representation concern­ing the need for, or the usefulness of, any goods or services

What happened to you with respect to the RO purifier fits into this explanation. I guess you can go ahead and file a complaint. If you want to take a look at the bare act, here it is -

Seetha Gopalakrishnan
India Water Portal Team

86. IS 28 ppm TDS in water safe for drinking or not?


In my area TDS level in water is 543 and after purifing the water with aquaguard reviva model current TDS is 28 .

Please tell me if the TDS level 28 is safe for drinking or not?

87. Taking action against manufracturers

If any one is selling water purifier whose TDS is less that the drinking range, why cant we take legal action against such manufactures? These manufactures should be punished because they are playing with the health of human beings.

88. How to increase TDS of water?

How we can increase the TDS of water if it is very low? We have to change our membranes or should we add some chemicals? Or should we do something else? Is adding chemicals good for human body?

89. Is it necessary to know the TDS?

Dear Sir,
I purchased an Aquaguard RO system few days back and I analysed some of the parameters. The following are the observations: pH - 7.42, Chloride is present, sulphate is absent and the hardness of water was found to be 45.1 mg/L.
Then TDS availability is not known. Today we had given the sample for microbial testing and is under process.

Do we need to know the TDS quantity?
Awating your reply

Anil Kumar Jha
QC Chemist (Pharma Industries)

90. Contact the people who set up the RO purifier

Dear Sir,

The people who set up the RO purifier at your place would have given you a slip which mentions the input as well as the output TDS. If not, please contact them to get the required details.

Warm regards,
Seetha Gopalakrishnan
India Water Portal Team

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