Backflow of sewage water into the house

[Brinda]

Hello all,

We have been facing severe sewage backflow / reverse flow into the ground floor of our house everytime it rains in bangalore
. We recently renovated our house and maintained the necessary slope , but in general our house is a bit at a lower elevation compared to other neighbouring houses. Moreover our outlet is right next to the main manhole on the road.

We have tried various solutions with chamber interconnections , but nothing has worked out so far.

Is there a reliable solution to pump out this excess sewage water which is backflowing from the main sewage pipe ?

Contacting BBMP all the time to clear the blockage is never efficient and we have to keep paying them bribes to do the work .

Can any one here help solve this in a more smart way so that we can be self reliant.

This always happens during heavy rains. Last year however despite the rains we did not observe any back flow and the house was newly renovated.

Yesterdays rain triggered this problem again

[SAMPATH S]

Please check how your rooftop rainwater is drained out. In a large number of houses, it is allowed to discharge through the sewage line. Even though this procedure is illegal, a large number of households resort to it either out of ignorance or due to situational difficulties or due to the wrong advice of the plumber.

During rains, a huge quantity of rainwater flows through the main sewage pipe and due to this a virtual wall is created in the main pipeline. When rainwater from the house routed through the sewage line approaches the main pipeline, which acts like a virtual wall, the water gushes back and flows out through all available openings inside the house, and solid waste already present in the pipe is forced out.

I have personally seen this happen in some houses in the RT Nagar BDA layout itself (particularly on roads with steep gradient). There was a great relief once the rainwater was re-routed to the storm water drain (ideally it should be routed to a pit for groundwater recharge).

Low lying houses are obviously more vulnerable.

If this is not the issue, then other modalities may be examined.

[srinihome]

Have you checked this product?
https://www.supreme.co.in/plastic-piping-system/product/backflow-prevention-valve/

[Brinda]

Hi Sampath ,
We have done rainwater harvesting , so all the rooftop water gets gathered into the RWH filter and is then routed to a sump( specifically meant for rainwater).

However the rain falling in the remaining open areas like the offset / main portico areas are routed to through a grating to the storm water drain .

And like you rightly mentioned my house is in the low lying area on the road , my neighbour are at a higher elevation and also the road slopes towards my house.

We have spent lots of money on renovation and had redone the plumbing line but still it is low.
My feeling is that there is back flow like you pointed out as that virtual wall breaks and sewage water from the main line gushes back in .

Calling Bbmp to clear the pipeline is not an effective solution , we have struggled multiple times to get them to do the work .

Could you suggest other solutions ? Can we get on a call sometime to discuss further ? I would be really grateful to any advice I receive on this issue.

[Brinda]

Hi Srinihome,

Yes I have heard of it , as my plumber suggested it . But have you seen it being installed in homes ? Has it really worked ?
Is it customizable based on the size of the pipe ?
Is it usually fitted at the output of the main chamber ( I.e., exit point from the house entering into the main sewage line )
I would really be grateful if you could shed some light on the above questions.

Thanks a ton for replying though. I really need the help and advice

[srinihome]

Brinda,

This is sized for a 160MM (6") pipe. If your main Soil Pipe connecting to the BWSSB sewage line is 6" then it's direct fitment. If your line is 4" you could use a reducer (160MM x 110MM) and connect this.
The Back Flow Preventer contains an approximately 15" chamber (square section) which has a top cover enclosure secured via hex screws and can be opened for maintenance purposes.

Yes, this should be added before connecting to the BWSSB sewage line.
If you ask me this itself can act as the main chamber (since you already have one place it after the main chamber before connecting it to the BWSSB sewage line. Please note to place this such that the top enclosure is accessible for maintenance.

Yes, we have installed this at our ongoing construction but I can't provide any feedback since we have not commissioned it yet.

Video Reference of the Product:
https://www.youtube.com/watch?v=LeIoHgtDgII

Reducer:
https://www.supreme.co.in/plastic-piping-system/product/eccentric-reducer-fix-o-ring/

[Brinda]

Hi srinihome,

Thank you for the information. Maybe i just have to install it and see how it works. Thanks you once again for the recommendation

[rreddy18]

We used this in our apartment. This allows water to flow in one direction and does not allow sewage water to enter. Very effective solution. It costs less then 3k for 6 inch and about 1.5k for 4 inch.

[Brinda]

Hi rreddy 18 ,
Thank you for your feedback . Just a follow up question to this . So during heavy rains what happens to the water flowing from within your apartment ? Does it get backed up ?
Have you face a situation where in the baked up water ( the one from your aprtment ) has to place no flow out and there is sufficient back pressure from the main sewege line and ends up flooding your apartment anyway ?

[rreddy18]

In our apartment , we have large pits so our own sewage water gets collected there during the heavy rains. Once the rainwater on the sewage line is cleared our water will flow back again to the existing drainage.