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Grey water System For Domestic Use : Design & Cost - Consultant Required

I am looking for Grey water system for my house to recycle laundry, bath water for flushing the toilet. Is there any system available in the market.

Its Ground + 1 Floor above, with total of 3 houses. Ground Floor 1200Sqft and First Floor each house 700 Sqft.
1. Users:  Ground Floor - 5 members
           First Floor Total - 6 members
           Total members per unit: 11
2. Laundry water 3 houses - Around 900Lts per week
   Bathing water 3 houses - Around 1000Lts per week
I want to use this water for flushing the toilets.
3. Current system: Have a septic tank of size L:9Ft x W:6Ft x D:7Ft : I am diverting only the Toilet waste and flushing water to this tank.
Also have a Soak Pit: L4Ft x W: 4 Ft x D: 7 Ft, I am diverting all the bathroom water, Kitchen water and the Washing machine water to this pit.

The issues I have are:

1. When we divert the water to the soak pit, the soil below is clay and the process of absorption of the water is very slow.  This creates a bad odor & it the water has to be pumped out every 2 months.
2. Most of the people in this area, divert the water to the adjacent vacant plot.
3. It would take 5 yrs or more for the underground sewage system to be implemented in our area.
This has prompted me to look at implementing a grey water recycling system. I would also like to know how much it would cost and the maintenance/plumbing requirement for it. Do pass on contact information of qualified people who would be able to assess the requirements and provide advice.






1. Grey water System for Domestic Use

Dear Rajan,


A home treatment system for GWT is possible, say the water in use per day is 1100 to 1500 lit res.


A house-hold treatment plant can be done to get around 800 to 1200 litres of processed water; the cost would be say 40 to 45,000/- per kl. i.e say 60 to 70,000/- and if with some aesthetics 10 to 15%...say within Rs.1.0 Lakh.


What is the plot size...processed water can be used for growing plants/ trees. 800 liters can water/ irrigate 300 sqm of greens, lawn, plants and trees, have peripheral trees, creepers, and some plants of plantain variety etc.

All the water is to be consumed in greens, or at colony greens etc, if you are positive enough for the above notings then a lot can be done.

It’s not good to leave all the waste-water into vacant- plots...what happens when it is raining..? Where is the site located?


Also send a PPT on the same subject for more info on WWT plants and its placement in plots, etc. Access here: DEWATS  PPT


All the best,


Er. Ajit Seshadri

Secretary and Head- Environment & Energy

The Vigyan Vijay Foundation

New Delhi-110 045

2. Hi: Thanks for the reply.


Thanks for the reply. Area of the plot is 2400Sqft, of which the built up area of 1500Sqft. We have planted some flowering plants (3 to4 )in the front and Banana plant at the backyard.

There is a septic tank, Sump, rainwater harvesting pit in the plot area, so hardly there is any space for effective gardening. My solution was to reuse the water for Flushing toilets & gardening to the few plants which we have.

Please clarify the below;

What would be the monthly fixed maintenance cost apart from the initial investment..?

Will the water be odour free ?

Would it involve any type of filters, if so life of the filters?

Is this system effective?







Madan Iyengar


4. Grey water system for dometic use- design and consultant require

Cnn you spare about 25-30 sq ft of soil area in the garden area in one place or more which get  of at least moderate amount of sunlight daily? Then I have a simple method using just water loving plants which will clean the used water.

The process operates on gravity, does not use any power or chemicals and is practically self-sustaining. installation cost will be  negligible. If  interested, you can buy a copy of book costing only 150 rupees where you will find exhaustive details of the method. You can thereafter get free guidance in installation and subsequent trouble shooting should the need for it arise. it has been working in several apt complexes since many years. The treated water has been certified by the Chennai Metropolitan Water Supply and Sewerage Board and can be used safely for flushing, gardening and vehicle washing.

Indukanth Ragade (

5. Need cost information to set up Grey water treatment


I am a student of architecture, doing my dissertation on Grey water treatment. I want to know what all is required to set up Grey water treatment systems ?

More over, how much area of land is required ? What would be the cost for a public project like Delhi Haat, if this kind of system is incorporated ?

My site is 5.5 acres and built up area is 6000 sq m. I want to know about the whole process.

Kindly reply.

6. Cost effective grey water system

This is response to your query submitted on 20th Aug 2012 on the above topic. I have established a simple eco-friendly system that is operating in many apartment complexes in Chennai for treating and reusing water used for bathing and washing of clothes. It involves only soil, sun-light, and water-loving plants, works on gravity and uses no power or chemicals and is practically self-sustaining. Its cost is also marginal if the treated water is allowed to percolate into the soil and charge the shallow water table. The cost involved in collecting it and using it for flushing, gardening and washing of vehicles will be dependent on the volumes involved.

If you indicate the number of users involved and confirm that the soil space needed (2.5 sq ft per person in any shape) is available, I can give more details.

Indukanth Ragade


7. Costing of grey water treatment plant


I want to know the cost of grey water treatment plant of 16000 liters/day capaity. 

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