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Unused Drinking Water - Recharge Options?

In our office work location comprising of about 300 employees, upon rough calculations, nearly 400 Liters of unused drinking water without any contamination is being drained to sewage.

 Reasons are:

1) replacement of leftover water in the waterbottles every day

2) Partial consumption of water from fully filled glasses of water by employees and the remaining half is being drained by canteen personnel etc.

I would like to prepare a proposal for redirecting the water to a recharge pit so that the drinking water from above sources can used for ground water recharging. Expert advice in this regard is highly solicited. Do advise me on the feasibility, practical aspects and if any precedence exists for such a plan.



1. GW recharge is just a method

GW recharge is just a method of storing water for future use. Its plus points are - it offers a very large storage space free of cost and free of any ground coverage. Its minus points are - it consumes energy to pump it out again and with falling GW levels the energy requirement is considerable; and if the GW quality at the location of recharge is not good then it amounts to mixing good clean water with poor quality water. 400 L is easily storable in a mid size Syntex tank. Instead of GW recharge, I suggest put a 500 L Syntex tank at ground level and empty all unused water in it. From this tank, see if there is any way to use it within the office for some other purpose. e.g.

a) for gardening if you have any plants/lawns etc. (if not, why not ? Do get some plants :-)

b) for daily cleaning/ floor mopping etc.

c) Are you using any desert-coolers? If so, use it in that.

d) Pump it to an overhead tank and use it for toilets flushing. A small 150 W pump is enough. (or use a hand pump and save on monthly payments to a Gym. :-) This will require having a separate OH tank and a plumbing line to toilets. But that is a minor one time expenditure.

Options a, b, and c will directly reduce your water intake from whatever is your source, and with option d the water after flushing will remain in the water cycle for some downstream location. All these options are more “green” than putting it in the aquifer.

Chetan Pandit

2. Unused Drinking Water - Recharge Options?

This 'unused' water shall be categorized as USED WATER and forbidden by law to use it for ground water recharge.  It is not ethical to dump used water in water table.

you will have to explore other options to conserve this water.

3. Dear Haripriya, It is

Dear Haripriya,

It is possible to recharge the left over bottled water and glass water for recharging as because both the waters are of drinkable quality. If the water can be exclusively directed towards a recharge pit then sub-surface recharging is possible. The recharge pit shall have gravel as base media and over the media coarse sand layer shall be kept. The gravel and sand thicknesses may be of 40 cm and 70 cm respectively. The approximate depth of recharge pit may be of 2.5 to 3.0 metres. However depth needs to be ascertain from the existing water table (unconfined) and soil charecteristcs. The pit size may be of 2.0 metre X 1.0 metre.


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 Haripriya, You are

Dear Haripriya,

You are talking about clean water that is not used in offices.This need not be sent to recharge pit.This kind of water need to be collected in the tank everyday. It can be used for drinking after chlorination.You can also pass this water through standard filters and reuse.

With best regards,

Abhishek Mendiratta
Jupiter Knowledge Management and Innovative Concepts
New Delhi

5. Dear Haripriya, Step 1 Reduce

Dear Haripriya,

Step 1 Reduce - Please provide 500 Ml bottle to employees as this will considerably reduce leftover quantity.

STEP 2 Instructions to employees and canteen people to drain water in a particular wash basin marked as "recycle only", if possible outlet should straightway go to recharge pit made in the ground.

STEP 3 If that is not possible; the same can be collected in 20 litres cans and can be used in horticulture.


Tushar Trivedi
Bottled Water Segment
Bottled Water India
New Delhi

6. Dear Member, I do not agree

Dear Member,

I do not agree that recharging groundwater with water otherwise fit for drinking is commendable.
The approach I would like to suggest is, first, to make efforts to minimise wastage by educating the employees and, next, to treat such water in a aquaguard type of unit and reuse it for drinking, preparation of tea/coffee or cooking (if there is a canteen).

With regards  

Paritosh Tyagi
Chairman (Retired)
Central Pollution Control Board
New Delhi

7. Respected Sir,I am very glad

Respected Sir,

I am very glad to receive your comments. i have the following doubts regarding your reply.

a) The drinking water which is proposed for ground water recharge is exclusively drinking water only.

b) A separate dedicated collection system, for collection of the unused drinking water only, shall be designed.

c) In such a case, the water if routed to ground water recharge pit of layers of sand, gravel, and pebbels,  it shall be of the quality of water at the outlet of an aqua guard which can be used for drinking purpose.

d) In the proposal also, the water being recharged shall be at par with drinking water quality.

Hence, request to clarify regarding disadvantages and advantages of dedicated collection system.

Your kind reply in this regard is highly solicited.



8. Dear Member, As soon as you

Dear Member,
As soon as you send the water to drain, it becomes wastewater. Besides, you have to agree that the water left unfinished may contain mucus and other contamination per glass of water consumed. The water must be therefore, collected and disposed separately after being filtered and sent to ground for recharge.
You may devise own collection system and disposal system by a dedicated PVC pipe to the recharge pit.
With best regards,

Taral Kumar
Executive Director
Akar Impex Pvt. Ltd.
Noida, Uttar Pradesh

9. Unused drinking water - Recharge options

Dear Haripriya
There are no grounds to say that it is forbidden to recharge used water. Chlorination and re-use is hardly an easy process. Chlorination is not very user friendly and if the water is over-chlorinated, it is worse to drink it rather that to drink the water without any treatment. It is also not correct to say that recharge of used drinking water is not commendable without giving the reasons for the same. The Tamil Nadu Pollution Control Board has three standards for disposal of sewage: The most stringent for discharge in water bodies, then for discharge on irrigated soil and the least stringent for discharge on un-irrigated soil. When disposal of even treated sewage is permitted, where is the risk in discharging left over drinking water on soil ?

It is unfair to raise concerns like these without adequate reasoning to back them up. Let me tell you, Ms. Haripriya, that nothing will happen by discharging the unused drinking water on soil directly. I am open to challenge here.

Let me give a few suggestions based on my long experience in the field on water management :

1. Water left over in glasses and bottles is not at all poisonous or will cause sicknesses unless the people who drank it were suffering from some sickness. You may have seen people drink from the same cup in many places from which earlier another had drunk while sipping. If the left over water were harmful, such a practice would have caused sicknesses widely.

2. Soil is the best treatment medium for removing organics from water. So, if you just put left over water on plain soil which is not very clayey, it will be absorbed and get cleaned by the soil. If you use it for watering plants, nothing deleterious will happen. I have watered banana plants even with water used for bathing and washing of clothes straight without any treatment and have harvested bumper crop of 300 bananas from one tree.

3. The attempt should be to reduce the wastage at the usage stage itself. Maybe you can place smaller glasses so that the person who is very thirsty takes several glasses and the person who is marginally thirsty will leave lesser quantity of water in the glass.

4. Most important: You are talking about water left over in the bottles at the end of the day. This indicates that you are providing individual bottles to your employees. If this is correct, then let me assure you that the water left over in the bottles need not be thrown away. It is still fit for drinking the next day and even a week later. Water kept in a closed container and which is free of organics does not deteriorate for months and even years!! So your problem is solved by not throwing away the left over water. The bottles may need cleaning once in a while, with soap water.

Indukanth Ragade (

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