Question
Asked 15th May, 2016

What should be the permissible limit of TDS in drinking water?

While using purifying system with RO for collecting drinking water, the water in many cases shows very low conductivity even less than 30 microS/cm. So TDS is much less. Whether such water is suitable for drinking? Will it not cause any mineral deficiency. Many manufacturers claim that they maintain controlled TDS in water but in most cases TDS is much less even less than 20 ppm. Kindly think of over this issue. 

Most recent answer

23rd Nov, 2021
Nivedita Sahu
Indian Institute of Chemical Technology
500 is minimum TDS for drinking water

All Answers (29)

15th May, 2016
Parashuram Sahoo
Indira Gandhi Centre for Atomic Research
I do not feel drinking water upto 2000 mg/L is acceptable for drinking. Such high salt concentration will lead to health hazard. Moreover my query is whether drinking water collected from purifier with RO having TDS less than 20 ppm is suitable for drinking. Will it not cause any mineral deficency?
1 Recommendation
16th May, 2016
Moruffdeen A. Adabanija
Ladoke Akintola University of Technology
The permissible limit as provided by World Health Organization (WHO) is 500 mg/l.
16th May, 2016
Parashuram Sahoo
Indira Gandhi Centre for Atomic Research
Yes, I do agree to this point. The next part of my query is to know whether we can accept water with TDS less than 30 mg/L for drinking purpose. If so will it not cause any mineral deficiency? My intention is to know at present many reputed companies supply water purifier with RO which gives less than 30 ppm TDS. How can we accept it. By paying huge amount for a water purifier we may land with another critical problem - i.e. mineral deficiency. I will appreciate to my friends in RG to think of this issue which will give a good lesson to common man 
16th May, 2016
Parashuram Sahoo
Indira Gandhi Centre for Atomic Research
Thank you Dr. Abhishek. I have gone through this link. It is really a good debate. But we have to think deeply from scientific point of view. 
1 Recommendation
18th May, 2016
Raja Rajamohan
HEAVY WATER PLANT- TUTICORIN
500 mg/L is the limit of  TDS for Drinking water stipulated by WHO as well as BIS.
18th May, 2016
Radhashyam Muduli
NTPC Limited
500 mg/Liter of TDS  for potable water as stipulated by WHO is not a limiting content on lower side. In a broad sense if unusable minerals are removed in RO process, it is no harm to use it for drinking purpose. As such, the purer the safer. The required minerals for human body may be available from food & diets. This is only a technical aspects of analyzing the issue. 
19th May, 2016
A. Adam Lagum
Isra University, Jordan
500 mg/L as suggested by WHO
19th May, 2016
Virendra Kumar Saxena
National Geophysical Research Institute
Permissible limit of TDS  in India is <  500 mg/lit.   This is fact TDS is reduced by using Reverse Osmosis ( 30 - 60 mg/lit ).  In concerned with minerals  after RO is useful to study.
19th May, 2016
Mysore Janardhana
Yuvaraja’s College University of Mysore
Dr. Sahoo,
A thought provoking question from the point of consumers.  When we opt for something which is against the nature, surely we must compensate for this.  In India, three kinds of water is supplied for consumption: surface water, groundwater and a blend of surface and groundwater.  In all the three, normally after the treatment TDS is brought down to less than 500mg/l.  There are exceptions to this.  Places which are not blessed with surface water resources, entirely dependent on groundwater and no facility for the water treatment, no piped water supply, water may be brackish with TDS more than 1500mg/l.  Surely the water will be enriched with nutrients.  When you go for RO or any other mechanisms to bring down the TDS content, one should be prepared to compensate the loss of nutrients  to human body by supplements.  As far as my knowledge goes there is no prescription as to the minimum value of TDS in drinking water.  
1 Recommendation
16th Dec, 2018
Sarfuddin Azmi
Prince Sultan Military Medical City
As much I know below 150 tds is not good for health. Most of water supplier supplying less than 100 tds and pH less than 7. As per the body requirement, TDS should not be less than 150 and pH 8.
16th Dec, 2018
Radhashyam Muduli
NTPC Limited
Drinking water is taken for adequate fluidity of food we eat in a day so that it can be easily digested. No extra minerals is expected from drinking water to supplement our body needs. It should be extremely pure and free from suspended particles with less than 20 jtu of turbidity. TDS 75 to 90 ppm is ideal for drinking purpose.
16th Dec, 2018
Radhashyam Muduli
NTPC Limited
Drinking water also provides a medium or channel to extract impurities from the human body. For this purpose it should be pure enough in terms of TDS to capture maximum impurities from the human body. Thanks
16th Dec, 2018
Mushtaq Ahmad
Pakistan Atomic Energy Commission
According to the BIS, the ideal TDS for drinking water is below 300mg/L and the max permissible limit is 600mg/L. It is recommended that people with kidney problem should drink pure water having TDS level below 100 mg/L for better recovery.
16th Dec, 2018
Saad Kariem Shather
University of Technology, Iraq
500 mg/Liter of TDS .
29th Nov, 2019
Bhairo Prasad Ahirvar
Indira Gandhi National Tribal University
The RO water is recommended whenever the drinking water quality parameters are not as per standard or exceeding the permissible limits. If we are talking about total dissolved solids, it also depends on all other parameters. So the TDS value should vary according to all other parameters.
30th Apr, 2020
Bashir Brika
Libyan Advanced Center of Chemical Analysis
I believe that one of the shortcoming in many international standards of water quality is the minimum permissible lime of TDS. For example Who states that the permissible limit for TDS should be 500 ppm or lees than 500 ppm but what is the minimum permissible limit? Certainly, it is not good for our health to drink water with TDS = 50 or 10 ppm.
10th Jun, 2020
Subhash Chavare
Krantiagrani G.D. Bapu Lad College Kundal
According to World Health Organization, TDS level less than 300 mg/litre is considered as excellent, between 300 and 600 mg/liter is good, 600-900 is fair, 900 -- 1200 is poor and TDS level more than 1200 mg/liter is unacceptable.
10th Jun, 2020
Raja Rajamohan
HEAVY WATER PLANT- TUTICORIN
I am a Water Chemist worked in this area for more than 39 years. 500 mg/L is the TDS limit for drinking water. If no any quality of water is available this limit can be extended or allowable upto 1000 mg/ L. My suggestion and as well WHO never drink water having TDS less than 100 mg/L. By drinking such waters we will be loosing essential minerals for the body which is normally removed by RO.
13th Jun, 2020
Radhashyam Muduli
NTPC Limited
Dear Raja Mohan,
Thank you for your reply and suggestions.
You will appreciate that water with ultra pure having TDS 70 to 90 is a good taste like a running river (Mahanadi)water quality what we get at Bhubaneswar Municipal corporation, in Odisha. With TDS more than 140 , it tastes like a ground / bore well water with enormous dissolved solids, like hard water and having less foam. As such we derive our essential minerals from our food and balanced diet. This purity of water may be able to clean our body by dissolving more impurities from our body system.
Can you please quote any practical problems faced by users of ultra pure water?
21st Jul, 2020
F. Bouteldjaoui
Ziane Achour University of Djelfa
Dear Dr Parashuram Sahoo
TDS (mg/L) < 500 : Desirable for
500-1000 : Permissible for drinking
1000-3000 : useful for irrigation
> 3000 : Unfit for drinking and irrigation
References
Davis SN, DeWiest RJM (1966) Hydrogeology. John Wiley & Sons, Inc., New York, 463 P
23rd Jan, 2021
Kiprotich Kiptum
University of Eldoret
Water use for irrigation should be less than 450 mg/l
1st Jun, 2021
Ibrahim Massaoud El-Azizi
Atomic Energy Establishment, Libya, Tripoli
WHO recommended that the minimum level of TDS for drinking water is 100 mg/l and the optimum is about 200 - 400 mg/l.
25th Jun, 2021
Aash Mohammad
Rajiv Gandhi Institute of Petroleum Technology
200-400 ppm TDS excellent drinking water for healthy person. If some one is not healthy and suffering some cardio and other diseases than water TDS 50 -150 ppm is excellent.
5th Nov, 2021
Najib Abou Karaki
University of Jordan
For practically illustrating some answers, Please would you drink this water?
8th Nov, 2021
Parashuram Sahoo
Indira Gandhi Centre for Atomic Research
Thank you all for submitting different types of answers to my question. Recently there is a big issue on recommendation of RO water for drinking purpose. water below TDS 500 ppm is not suitable for drinking purpose as mentioned in various specifications. Towards this I want to mention that the specifications which mention a minium TDS value of 500 ppm for drinking water will be accepted assuming that water of that TDS should contain minerals such as useful salts of Na, Ca and Mg etc. which are really useful for every body. But we cann't be ensured that only useful salts will be present but not heavy metals such as Pb, As, Fe,Cr, Ni etc., fluoride and nitrate salts, chemical toxicity due to contamination of waste chemicals in soil and water discharged from various chemical industries, contamination of sewearage in water especially in city areas. All these contaminations can be removed from water using RO technique in most simpler way. Hence my suggestion is to use RO water after remineralisation with useful salts or RO with adjustable TDS facility. Such water is the best one for drinking purpose which can supply you a clean source of water with useful minerals added in controlled way. Another easy way to add trace quantity of rock salts to RO water for drinking purpose. Rock salt contains above 98 % NaCl and about 50 to 60 ions in trace level which are useful for human health.

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