Sump water tank on top of a foundation? Will this create additional load on the foundation?

This is a common question that we get asked a lot. The short answer is yes, we can do it However, it's not always the best solution, durability point of view. A sump tank is a water storage tank that is usually underground. Many times, there may not be enough space in the ground floor to accommodate tanks. The reason is a tight plot where the client wants to build as much possible. When the site is tight, it is difficult to accommodate space for services like water tanks. Then the structural engineers are asked to explore possibilities of accommodating it between footings. Some times this may not be possible if the footings are closer. The next preferred location may be on top of footings.
Waterproofing a sump tank is important. It protects the foundation reinforcement from being corroded.
Another structural point to ensure is the depth of excavation. The water tank base shall not be below footing base. If you do this, then the stability of the building itself might be affected. It can lead to the footing load or surcharge being passed to the side wall of the tank. It is not sensible to design the tank base for this pressure. If it is not designed the side wall of the sump tank can fail or can have severe cracks and leaks. It can even lead to failure of the building.
All these aspects are mentioned in the video clearly with sketches.
As a summary
We can have tanks on top of a footing
The tank shall be water proofed to avoid any leakage that can lead to corrosion of rebars of footings
The level of water tank base shall not be below the footing base as this can lead to instability and collapse and other structural issues.
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[@luckyali4586]

Thanks I was little confused, watching ur Video helped me.

[@CIVILERABangalore]

Great to know the video helped you. What do you do? You are a civil engineer or were looking for a solution while building your own?

[@vijayalakshmi.s9207]

THANKYOU SIR NICELY EXPLAINED

[@CIVILERABangalore]

Have you joined my groups?

[@niteshbatham7752]

Important knowledge for civil engineer ❤️

[@CIVILERABangalore]

Nitesh, Nice to know you liked it :-)

[@SUNILKUMAR-bh9jm]

I was suggested to build soaking septic tank inside the house foundation, it will be center of four columns , which means septic water will be observed by earth and the columns can get these wet, Will this damage my columns or footings over a period of time?

[@CIVILERABangalore]

Consult a well experienced structural engineer in your area. It is not possible to advise on YT comments as there are a lot of parameters that needs understanding before we can advise

[@allabakashm3823]

Good information sir.

[@CIVILERABangalore]

Nice to know you liked this info :-)

[@khalifaalnaamany9330]

Hello I am not a civil engineer , I m trying to build a car garage with a swimming pool on top of the garage , the garage is 10m x 6m garage with a swimming pool of 8m x 5m and 1.5m depth with six footing and pillars, what size of footing should I use to be on the safe size, thank you

[@CIVILERABangalore]

Please consult a Structural Engineer in your area and explain and get this designed.

[@SadamHussain-fr5ji]

Can we keep septic tank above footing. It is build with normal brick and not concrete

[@CIVILERABangalore]

design and load point of view, it is ok assuming the footing is designed by a structural engineer. durability/leakage etc needs to be attended

[@ngasepam492]

Will there be any problem if the columns are made part of the tank...like having a common foundation plate and columns stand at the corner of the tank

[@CIVILERABangalore]

Can be done but proper attention and design needs to be done.

[@christianhindang621]

Good day sir, what if my Cistern Tank is also my structural Footing foundation, would this affect my structure's integrity? thank you

[@CIVILERABangalore]

See, there will be a backfill of soil in general cases and density of soil is 20kN/m3 approx. And water weight is less than that of soil. So generally, weight point of view, there is no concern. Only issue is durability when footings come in to contact with water if ever it does. Provide cover and ensure quality.

[@kagosobin9827]

Sir i hv made a base of septic tank with equal to footing without water proofing ..will iron rod of the footing get rust and corrosion after some time?

[@CIVILERABangalore]

May be may not be. depends on the nearness and leakage

[@kagosobin9827]

Sir plain footing with thickness of 5 inch can carry load of g+2

[@CIVILERABangalore]

@@kagosobin9827 If it was such an easy thing to say by chats on KZbin, then why should structural engineers be on earth 🙂 Please consult a structural engineer in your area and solve your problem

[@kagosobin9827]

Thank you sir for ur advice

[@vasanthregula8970]

I have a situation, where i have to build sump 2 feet adjacent to the footings. If I take care of building the depth of sump equal to level of depth of footing. Is that ok? Or do I need to reduce the depth of sump to bring it above the footing. Please suggest.

[@CIVILERABangalore]

Well, Generally it is ok provided what I understand is correct. However this can be established only by more careful discussions. Are you a civil or structural engineer? I cannot advise you any thing based on text chats and on YT. You need to get the actual design done if you are constructing this

[@miqbalhundekari4802]

I build first tank leaving footing area but second rank building on footing my steel designer said to make 6"solling above footing and surrounding area ,what may be reason for solling?

[@CIVILERABangalore]

Best would be to ask your engineer. I can comment if I know about the project. What information you have mentioned is not adequate for me to say any thing

[@ksreedharangayathri]

Is it okay to place a column on top of a water tank which has 9cm rcc roof?

[@CIVILERABangalore]

The info you provided is not adequate to provide an answer.

[@chtahnamte]

What if the column comes in the middle fo the tank

[@CIVILERABangalore]

Better to avoid. If un avoidable, do proper water proofing and load take down as needed

[@miqbalhundekari4802]

Either continiously Dead load and live load effects water tank on footing ?

[@CIVILERABangalore]

Please explain your question

[@abidmulla1561]

Hello sir ,If instead of sump tank if there is retaining wall where should we place , 1. Wall base above above the footing 2. Wall base below the footing which is more safe

[@CIVILERABangalore]

Depends on various things. But Retaining wall footing cannot come below the column footings when they are overlapping in plan. You can even have common footing where they overlap and accommodate it in design

[@ganapriyaprakash]

Hi, i did strip footing for my house foundation 130 cms base and top 20 cms for beam, in our work area having size 192cms* 300 cms after only a small square piece of land will be balance after footing,so we did reinforced the total space of 192 * 300 and converted it into a water tank, as per this video if there any problem, Thanks..

[@CIVILERABangalore]

You cannot and should not do any work based on this video. Your understanding of the video may be different or the real conditions at site may be different than what you think. Always consult a structural engineer before and during construction. If you need any consulting services, please feel free to contact me

[@ukulelehudugi]

This information is very valuable! Thank you. However, sometimes clients are specific about needing a sump in North-East, and a column is present there, is it okay to provide a column in the middle of the sump? (With proper water-proofing). Thanks in advance.

[@CIVILERABangalore]

Not ideal to do Sumana. It can create durability issues. Can I know what do you do and have you joined my group?

[@ukulelehudugi]

@@CIVILERABangalore Sure Mr. Premjit. I work in Mysore, as a Civil Engineer (in training). Which group Sir?

[@mohammedsafwaan9525]

2:16 Hello sir, Will the load coming from rcc walls and slab of the tank not affect the footing as its density is higher than that of soil?

[@CIVILERABangalore]

@@mohammedsafwaan9525 Use logic and simple calculations Note 2 points 1) The density difference is minor 2) Even if concrete is denser, we are replacing quite a lot of soil with water. so water is less dense. You can calculate total weight of soil and compare with that of rcc tank + water.

[@abishak3506]

Nice sir

[@CIVILERABangalore]

Nice to know you liked it :-)

[@mahamed1212]

What about masonry wall on foundation

[@CIVILERABangalore]

Depends on if the masonry wall is carrying any slab load. If not, it is not denser than soil. So no issues.