# How to fill Cistern



## Daniel Holzman (Mar 10, 2009)

Cisterns are often filled with structural fill, which is typically crushed stone or a crushed stone/sand mixture. If the material is compacted as it is placed, you end up with a very strong fill that is capable of supporting a concrete slab. Check with your local building inspector for permit requirements, and definitely verify that there are no utilities in the cistern that need to be relocated or protected during the filling process. This is not a DIY project, unless you have a very small cistern.


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## mathmonger (Dec 27, 2012)

That is one of those jobs. Nothing sexy about it. Nothing to show for it. Just a money pit. Literally. 

Yeah. You don't want anything soft or organic in there, obviously. And you don't want smooth, round rocks either. You want something sharp and jagged that will lock together and resist settling. Crushed stone is ideal, but you pretty much have to pay what it costs. 

If you're highly motivated to save a buck, maybe you could get old bricks or concrete for free. Smash that up with a hammer. Might work, especially if you mix in some crushed stone as well.


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## Bondo (Dec 8, 2007)

> Q: What is most economical method of filling and suitable to have concrete slab poured over top.


Ayuh,..... What's goin' on top of this concrete slab,..??

Why pour a slab cap at all,....

Fill it with compacted dirt, most any dirt will do, if the final grade were to be lawn,...

1st thing I'd do is punch some holes in the bottom to let any water out of it,.....


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## ryansdiydad (Aug 16, 2015)

Crushed rock... U got a truck or an SUV? Head over to a legit landscape supply yard and load it up with some crushed limestone or the like.. Wont cost ya much just some sweat and maybe some sore muscle from shoveling a few hundred to a couple thousand pounds of rock


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## BriarVance (Aug 2, 2016)

Thanks for sharing guys. Its helped me a lot. Have a nice day


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