# Forum Home Renovation Water Saving Garden Ideas  Underground concrete tank

## Micky013

Hi all, 
Just wanted to get some ideas re underground tanks. The way my roof is built i have the ability to collect a lot of water at the back of the house. Recently i priced two concrete tanks - a 13,000 ltr for $4,500 and 23,000 ltr for $6,300.  
Just wondering if anyone has an idea of what the associates costs are? Excavation, crane etc. apparently i need to sit the tanks on a concrete base as well.  
Would i be looking at around 15k to get the bigger one in? I figure if possible, to try for the bigger one if im gonna go to the effort. Dont really have the space for a substantial above ground tank.  
Cheers guys!

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## Oldsaltoz

Perhaps you should also look at getting the tank built on site, no crane or foundation slab required.   
Good luck and fair winds.   :Smilie:

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## Micky013

Thanks mate i hadn't thought of that. Will look into it.  
Cheers

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## Draffa

One option I looked at a few years ago was to build a tank out of Dincell plastic bricks (lost formwork), and top it off with pre-stressed concrete beams so I could build a shed on it.  I can't remember the prices offhand, but they were pretty reasonable compared to besser-brick style construction.
Another option is tilt-slabs, but ensuring the corners are properly sealed might be a hassle.

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## phild01

That Dincell system looks interesting!
I would have expected reo but the graphic doesn't show much about this... as though it isn't used!

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## Draffa

Up to a certain height (I can't remember what it was, but it's in the literature somewhere), no reo is needed.  Above that height you only need vertical reo, and beyond one strorey, I think, you then need to start putting in horizontal reo as well.
So for an underground watertank you'd probably only need the vertical reo, plus something at the top and bottom to tie into the slabs.

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