# Filling in an old septic tank /cistern



## troyce1 (Oct 9, 2008)

While digging footers for our new deck today we discovered an old underground feature. 

It is most likely an old septic or outhouse tank, or possibly a cistern.
Its about 4ft wide, and 5 ft deep, with stone and dirt walls. There are no pipes or things running into it, and no water is in it.The house was built in 1850 so who knows when it was put in, or covered over. 

We are going to fill it in with gravel. 
Two questions
1 - What size and type of gravel should I use
2 - I wanted to build a rainwater leech can I use this pit for this, and if so how should I build the piping.

Thanks


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## Wildie (Jul 23, 2008)

Course pit run gravel should be fine!


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## Termite (Apr 13, 2008)

Be sure to perforate the bottom of it with a machine so water will leech out of it. A lot of people bury their downspouts and direct them to leech pits filled with gravel. Not a bad idea if it is far enough away from the house....10 or 15 feet at least.


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## steel baron usa (Dec 29, 2008)

*pit*



troyce1 said:


> While digging footers for our new deck today we discovered an old underground feature.
> 
> It is most likely an old septic or outhouse tank, or possibly a cistern.
> Its about 4ft wide, and 5 ft deep, with stone and dirt walls. There are no pipes or things running into it, and no water is in it.The house was built in 1850 so who knows when it was put in, or covered over.
> ...


i would put a little cw pipe in there and cover with crushed 57's
have to be crushed you get a 98% compaction rate with this.
then you would have your own retention pond.
connect a lead a pipe out if you want and filter drain half way down on the back.

good luck
peace


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## Knucklez (Oct 21, 2007)

i have the exact same problem! the cistern is not that big however, maybe 4'x4'. you can easily build a deck around this and then your cistern will be under your deck when you're done. 

then you can run your down spouts into the cistern to collect water and a submersible pump to supply your graden irrigation system. all under the deck and hidden away. 

that's my plan anyway 

Knucklez


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## 4just1don (Jun 13, 2008)

if your NOT filling with gravel etc,,,make DARN sure kids cant crawl under deck and fall in,,,they are TOO valuable to lose this way!! Most of those walls are real suspect and OLD, and may break in unless filled. I doubt anyone could survive long in cold ground water,,,let alone a kid. I could see gravel filled and drain out into a better suited tank for garden water.


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## Knucklez (Oct 21, 2007)

yes, good point. in my case, the cistern is covered by concrete lid. i didn't even know it was there for years until i found it by accident while residing the house. the only access is a hole cut in the concrete about 3inches square this small entry is also sealed with a lid. so its safe from the concerns you listed.


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## AllanJ (Nov 24, 2007)

So long as it will be "permanently" under a structure such as a deck I would fill it in with either gravel or soil and not run water into it.

If it were to be used to catch water (and not have anything built over it) I would leave it hollow and properly covered.


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