I have a building which sits on top of clay ground so I couldn't soak away the grey water.

I explored solutions like leechfield,soakaway,cement ring well but all fails in clay ground.

I'd like some insights on how to handle the grey water coming from my building. approx 1800L per day like some technique to send the water into earth or is there any plant which can consume high level of water ?

There's no underground drainage system provided by local municipality as well.

The ground water table is at 8 to 10 feet(Salt water).

The town is part of bigger river delta(Kaveri or Cauvery)

I'd like to have a solution and manage the side effects as well

Any help would be appreciated


Building layout

  • I have empty ground on right and back side of building , as the ground is expensive I can't buy and use that as leech field

  • The building has 3 houses one in ground floor and two in upstairs so it's like 10 or more people living in the apartment at any given time and with number of people are more so the grey water. The grey water is coming from washing clothes/utensils,bath room etc..

Here is my building foundation design

Building foundation design

  • I know RAFT foundation is best for any type of soil including saturated clay.

  • My ground soil seems to be either clay or saturated clay

  • I've asked for local professionals advice here are some suggestions from them this includes my own research as well

Solution 1:

Three cement ring wells ,one for each home and they said I'll have to keep the ring well between the pillars with 5 or 10 feet gap between each other. Each well should go upto 10 feet depth and last two feet has to be filled percolate materials and if water overflows then I will have to ask for moving tankers


  • Seems best one


  • I'm worried it might cause one side of building to sink as the soil might get loosened and some local professionals are agreeing that it could happen they can't guarantee but they said it's not likely to happen

Solution 2:

Buy the neighboring ground and use it a leech field


  • Seems good option as I don't have to dig any holes are which might affect building foundation


  • The ground is really expensive and not a good investment as the price might not soar much compared to other areas in town

  • There's a good chance someone might start construction in this empty plots in next 5 years which is good for my building foundation as well

Solution 3:

Build a underground storage unit made of concrete and keep the bottom open as there's a chance for water to drain and water remains transport it out with moving tanker truck.


  • Seems quite simple to do


  • It could become expensive as I have to build structure with concrete

  • This also might weaken the foundation

Solution 4:

Recycle the water and use it for toilet flush


My water dependency reduces and it's environment friendly


  • It's expensive and might be hard to get some kind of certification from the government.

  • Not really sure about the smell and microorganism

My Opinion:

I'm not really happy with solutions given by local professionals as they're dishing out suggestion based on their hunch rather than some technical analysis. I find their suggestion could become unreliable.

I'm looking for a solution which will not cause any damage to my building foundation and will be in reasonable cost.



Please find my soil texture below

enter image description here enter image description here

Reference for soil texture: https://www.yumpu.com/en/document/read/6730715/cauvery-delta-zone-status-paper-tnau

  • 2
    Some climate information would be helpful. I have built in areas of heavy clay with a mound system for all the sewage effluent of a large home. Adding trees like weeping willows can help but more information in the question would be helpful.
    – Ed Beal
    Commented Oct 15, 2021 at 21:46
  • 2
    You need a local soils engineer -- not randos on the internet. Commented Oct 17, 2021 at 20:02
  • 1
    1,800 liters (475 gallons) per day?! That seems like a crazy amount of water. You need to contact a professional that is local to your area to handle this problem.
    – Aron
    Commented Oct 18, 2021 at 18:11
  • 1
    what's the point of putting a bounty on this question? ... you need local professional involvement on this ... stop wasting your time waiting for some answer that may not ever materialize
    – jsotola
    Commented Oct 18, 2021 at 19:29
  • 1
    This question has bounced around for a while. Everyone here would love to help you, however, I don't think that anyone here has the expertise or knowledge to be able to do so. As many others have noted, you're going to have to go with some local expertise on this one. You've asked the local pros what is best, yet you don't want to go with their solution. Ask neighbors what they're doing and follow the most common answer you get, whether you like it or not. Sadly, we're just not in a position to help you with this one.
    – FreeMan
    Commented Oct 19, 2021 at 11:59

2 Answers 2


You have done the research. You want hard calculations on water? You will never get them. Water is fluid, always changing. A concrete answer to the paths and contents of water does not exist.

If you want this problem solved, you have only one choice: Buy the lot next door. Investment is risky and you will have to maintain more. When I sit and consider everything, none of the other solutions, although sensible in their own way, are actually reasonable unless you have more space.

My daughter purchased a home in an area whose ground is much like yours. High clay content where water sits around just about everywhere. High salt water level (near lake Erie), so you can forget about a well. The solution enacted in that area is simple: Nobody is allowed to own property smaller than two acres. Some things just cannot be done on a postage stamp.

  • I'd like to buy the nearby plot but it's really expensive.My problem now is like I couldn't settle with any options.
    – CuriousMan
    Commented Oct 19, 2021 at 16:22
  • I have almost 270 feet of empty space in rectangle shape(4.5 * 60) ft parallel to the building. as I showed in the above diagram
    – CuriousMan
    Commented Oct 19, 2021 at 16:23
  • 2
    4.5'x60' is incredibly narrow. As you said, you are afraid to dig there due building proximity. Not enough space is not enough space. Denial, denial. I worked for land lords a couple time. All that matters is cost. No love. No pride. If the apartment building cannot support itself, then sell it. Problem solved.
    – Paul
    Commented Oct 21, 2021 at 22:54
  • Now I realise buying the next lot is best option in long run
    – CuriousMan
    Commented Sep 12, 2022 at 17:48

Try flow-well Drywall or try something like this. It should do.

enter image description here

So its basically a container with some slots so that water can be discharged at all the levels of sand. It's better and can contain more water than soak pit.



  • It doesn't do well on clay soil and they recommend to keep it 10 feet away from building
    – CuriousMan
    Commented Dec 16, 2021 at 9:59
  • Agreed , it might not be effective enough on rainy season but if you lay 1 feet of gravel around the dry well then it should be good enough in non-rainy season and also you could dig a trench and install French drain with perforated pipes and cover that with gravel
    – Amogam
    Commented Dec 16, 2021 at 10:04
  • I don't expect the system to work so effectively like in sand soil but if it's good enough except rainy season I'm happy with that but I'm afraid it could loosen the soil around the building or could cause some water damage to building foundation or wall
    – CuriousMan
    Commented Dec 16, 2021 at 10:06
  • 1
    Your building is located in clay sand on river delta region, your building is already sitting on damp soil I mean saturated clay and I don't think couple of dry wells could affect your building unless you keep it near by foundation pillars. I saw you building foundation design pic you attached above and I think you can go ahead with drywells
    – Amogam
    Commented Dec 16, 2021 at 10:19
  • I'm just afraid that it making the saturated clay even more wet would cause differential settlement and which in turn can cause cracks to develop
    – CuriousMan
    Commented Dec 16, 2021 at 10:25

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