1) How to Repair Concrete Drinking Water Tanks Leakage from Cold/Construction joint? 2) How to Repair Leakage from Base slab?

thanks for this 

___ need to know where the leakage is . cement based on ipoxy

__ replace the tank to new 

That's a difficult one, first you need to know where the leakage is. The best way long term is cement injection, or cement based on epoxy (look at the type with drinking water!)

Also see if the leakage isn't to big so contamination can come inside!

1-Determination the leakage and try to close it by any think related to tank if the tank water full and need urgent solution

2-replace the tank by new one.

Hi,

Thera are a lot of solution, It's necessary to no what kind of concrete is used in your case and waht's the reason of leakage( corrosion or lixiviation or jut a cracks due to pression of water).

I can give you the solution if you have these inforamtions.

As pre-solution, you can use the ciment marine paste.