# Forum Home Renovation Waterproofing  Waterproof concrete tank at outlet point

## Onemack46

I have as my only water supply a concrete tank which is becoming corroded and leaking as the old GI socket rusts, I am seeking ideas as to how to fix this without emptying the tank. The only solution I can think of is to concrete encase the outlet. Even if I emptied the tank the outlet is too rusted and fragile to repair

----------


## Bros

You are going to replace the tank sooner or later so why not get a new tank and pump all the water there then totally empty the tank and do a proper repair with it dry.

----------


## Onemack46

> You are going to replace the tank sooner or later .

  That assumption is not necessarily correct and assumes, 1) I have sufficient funds 2) The tank is otherwise defective 3) that I live in a region where it is easier to replace than repair or renew. 
Do you actually see a flaw in the idea of concrete encasement?

----------


## Bros

I have been to some very outback places in Queensland and getting tanks is possible. As for the repair you seem to have a rock close to the side of the outlet. Concrete will set underwater but I don’t know if it is possible with water pressure and dirty concrete.

----------


## Onemack46

> I have been to some very outback places in Queensland and getting tanks is possible. As for the repair you seem to have a rock close to the side of the outlet. Concrete will set underwater but I dont know if it is possible with water pressure and dirty concrete.

  Please stop with the assumptions and gratuitous observations. The rock is there at the moment to hold the pipe in such a position that the water does not spray everywhere. I have no intention of pouring concrete over the existing situation. FYI I would clean all surfaces as far as possible. I would box it out to a depth/width of 150 mm where possible. I would use form-ply to box it out. I would use a concrete mix that is waterproof when set. I know the rust that is self evident will be a problem akin to concrete cancer simply because i cannot be as aggressive as i would like to be due to the fragility of the pipe. 
It is a concrete tank not mains pressure there are many products on the market for concrete tank repairs under tank pressure, none of which is suitable in this situation. 
 As far as getting tanks in outback Queensland being possible, that is delightful to know I often wondered where they came from when I worked in the outback of QLD, NSW, SA, NT and WA, Unfortunately apart from budgetary restraints, I am not in those regions. 
I will try and make myself a bit clearer, I did not ask how to concrete encase but sought alternative solutions and ideas

----------


## Bros

Best of luck. I gave you my suggestion and you sent a nasty reply not the way to get information I’m certainly not a mind reader.

----------


## phild01

Can you seal the outlet inside the tank with plastic sheet and a potable sealant. Test the outlet for any leaks and remove it. Chemset a new outlet and break the temporary plastic seal. 
I thought the advice you got already was relevant and practical.

----------


## Marc

That is an easy repair with the appropriate plumbing parts. 
There are expanding plugs to be used when there is no access to the inside. You could plug the old outlet and drill a new one or simply have a pipe over the edge and into the tank to siphon the water out.
Or you could call a plumber

----------

