You may login with either your assigned username or your e-mail address.
The password field is case sensitive.

Rainwater and Grey water system costs.

I am a postgraduate student currently studying at the University of Sheffield. I am now in the middle of my Masters in Sustainable Architecture Studies.As part of completion requirement of my Masters degree I require to write a dissertation. The topic I have chosen for this purpose is ‘Rainwater & Grey water systems in Islamabad, Pakistan’. I am studying the feasibility of collecting and reusing rainwater and grey water in households and public buildings and conclude that there will be significant decrease in water demand if measures are taken for each household and public building in the city incorporates this concept in its function.

For the purpose of this research I am looking for costs with reference to water tank sizes. I saw your post on the India Water Portal discussion board and I thought you might be a good eprson to ask for help in this regard. Also, I believe you are a company based in India and that is even better since UK prices largely differ from the sub continent prices.

If I can give you the tank size for both rainwater and grey water system do you think it will be possible for you to give me a realistic cost estimate?

I would be more than obliged if you can help in this regard as I am unable to find any other source in the same region.

Hoping to hear from someone soon.



1. Sintered plastic tanks cost

Sintered plastic tanks cost Rs. 3.5 to 5.0 per liter capacity, and are available in sizes that range from 100 L to a few thusand L.

Chetan Pandit

2. Dear Sannah, Greetings from

Dear Sannah,

Greetings from KSCST.
I appreciate your interest in Water Conservation and Rainwater Harvesting. I will provide the cost of the structures as required by you. You may send me the size of the tanks and the purposes.
With Best Regards,
A.R. Shivakumar
Principal Investigator - RWH,
Karnataka State Council for Science and Technology,
Indian Institute of Science,
Bangalore 560 012

3. Dear Sannah, For your

Dear Sannah,

To gather information, you need to assess the usage, and the water availability in the said location.
Consider rainwater for higher end uses like drinking and others.
Recycled water from Grey- water could well go for flush- water and horticulture/ agriculture uses when remedied and compliant to standards.
Rain water Harvesting:
You need to evaluate the rain catchment that can be stored for future use.
On an urban-area of 1000 sqm, effective run-off would be an average of 0.8 for hard/raod surfaces to 0.3 for greens area i.e can be considered as 0.5 times the rain fall.

For example Delhi, gets rain 0.7mtr.. therefore the effective rain catchment would be area times run-off times rain fall i.e 1000 sqm x 0.5 x 0.7 m = 350 cbm/ kl 350,000 litres.

If you consider a plain sump to contain the water Rs. 6000/- per cbm./ kl it is not feasible to make a big tank to contain all rain- water. If you consider part storage and part for recharge to ground then it would be needed to assess a system for taking rain water to charge ground water aquifers, which is usually done in areas whch get rain fall more than 200 mm/ 20 cm.

In areas of less rainfall (> 200 mm.)  as in Rajasthan in India rain water is stored in basement- look alike tanks in habitats.
A rain water harvesting system would require to be specifically designed to contain / collect rain- water / filter it / and then take it for recharging ground- water using an artificial bore well (usually bore- wells are used for extraction of water but recharge wells are termed as reverse bore - wells) cost will have to be evaluated on design basis.

Grey water recycling

Grey water recycling has been introduced by a few housing areas, township- developres etc.

A system costs between Rs. 20,000/- to 30,000/- per cbm./ kl using natural bio- remediation systems..whose O&M costs are lesser than the mechanised STPs .   

For a system of 10,000 litres ensuing from 20 homes x 5 persons x 100 lit per day per person cost of a system would be 200000 to 300000 INR.
Availbale water would be 300 days x 8000 litres.2400 kl. cbm
Refer to there attachments to give some idea on costs of the WWT systems of 6 plants etc
Pl feel free to clarify any information

With well wishes,

Er. Ajit Seshadri
Secretary and Head- Environment & Energy
The Vigyan Vijay Foundation
New Delhi-110 045

Er. Ajit Seshadri,Head- Environment, The Vigyan Vijay Foundation

4. Thank you all!

First of all I would like to thank all of you for the very informative responses.

Secondly, as for my research and proposals. I have calculated the total average water consumption of a household and the rainwater collected, while considering the coefficient of various surfaces. 

For household, according to my calculations

Total water consumption = 52,560 gallons per year

Water consumption (toilet, lawn and miscellaneous outdoor activities) = 23,725 gallons per year

Rainwater potential = 73,886 gallons per year

Grey water produced = 92,345 gallons per year

Please note that provision of drinking water is not part of my topic. Also, from the above results I have calculated the size of tank required. This was done using a web-based tank size calculator (UK website). 

2700 litre tank is required for rainwater system fr this house. i discussed with an Indian based water company that a 2700 litre tank would cost approximately 0.5 US Dollars per litre.

QUESTION 1 : Can anyone help me in calculating the tank size fr a grey water system using the value of the total grey water produced? and along with that the price of grey water system with reference to that tank size?

I am doing a similar process on a public high school of about 500 (students + staff). Results are as follows.

Total water consumption = 2,745,740 gallons per year

Water consumption (toilet, lawn and miscellaneous outdoor activities) = 2,400,740 per year

Rainwater potential = 1,091,454 gallons per year

Grey water produced = 3000 gallons per year

I am unable to calculate tank size for this building, the calculator I used for household dees not work on other buildings apparently.

QUESTION NO. 2: Can anyone help me in calculating tank size for rainwater & grey water systems for this school with reference to the amount of water collected? and also the price of the system?

5. Grey water estimates

Dear Sannah,

I think you can do it yourself; I am attaching Greywater tanks estimates and a link for rainwater harvesting tanks estimate rest you have to do.

With best regards,

Abhishek Mendiratta

Jupiter Knowledge Management and Innovative Concepts Private Limited (JKMIC) New Delhi

6. Rainwater estimate?

Hello Abhishek,

I received the grey water estimates via the link you posted and they are very useful as I can quite easily calculate the estimate costs.

However, the rainwater system estimate was not there. I would be much obliged if you can post those as well.

Just wanted to confirm these are the rates prevailing in India at present, correct?

Thank you very much once again. Hoping to hear from you soon.



Sannah Ejaz

7. Rates

Hi Sannah,

These are existing Indian rates.

8. Water tank

Dear Sir

We are a collapsible tank supplier from China. There are two kinds water tanks to choose from, one is the flexitank which can be used in 20ft container, and used for transporting fluid in 20ft container. It saves more cost than IBC tank. Another is the water bladder which can be used often for storing fluid in the ground and can be used for many years. If you are interested in it pls contact us. I will send more information and pics asap.

Best regards

Sky Yi

Room 718 block B, Tai'anxuan,Tairan Rd 9
Chegongmiao Futian District , Shenzhen City.CHINA
CTC: Mr.Sky yiMOBILE: 86—013164714743
FAX: 86-755-29073753
Skype: yshzh37

Post new comment

The content of this field is kept private and will not be shown publicly.
This question is for testing whether you are a human visitor and to prevent automated spam submissions.
3 + 0 =
Solve this simple math problem and enter the result. E.g. for 1+3, enter 4.
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 India License.