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Discussion Starter · #1 ·
External sump pit, or 'dry well'.
Used to lower the water table around a basement foundation of a house with a high water table. 7-10' deep by 24" dia vertical drain pipe, holes at the bottom, #4 backfill, pump at bottom.
Works the same as an internal sump but keeps the noise outside.

I'm considering installing one for a customer who's internal sumps run frequently.

Tips, tricks, ideas, opinions?

-JT
 

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It seems like you would need to intercept the water at more than one place, like a curtain drain or have bed of drain rock and piping under the house already for it to work
 

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Discussion Starter · #4 · (Edited)
The house has perimeter formadrain and gravel under slab.
Depending on the seasonal levels, the water table can be higher than the basement bottom, but the drain/sump system keeps the water down and basement dry. They just run a LOT. It was a dry hole when they dug the basement but then it filled with 1-2' of water when they returned couple days later to set the forms.

A little sketch...
 

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It will work if the pump is big enough. It will also make sure the homeowners electric bill is big enough:laughing: especially if you have highly permeable soils.
 

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Pretty common in my area. When I do this I dig down to the footing or just a bit lower. Powerwash the wall then have another company come in to seal it. Lay 4'' perforated drain tile on footing entire length of wall to be drained, this tile will later dump into the vertical pipe that holds the pump. The vertical pipe needs to have it lowest point about 12-18'' lower than the footing so that the pump is well below the footing. In this lowest point I mix a couple bags of sack-mix and set the vertical tube in it. When the 'crete has cured you can dump the 4'' perforated into it and backfill. Drop your pump in from the top and your set....
 

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From the title of the thread, I was hoping that you were going to post a pic of a supermodel.
 
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I don't gather that the OP has a footing already installed as Williams has described...do you? if you're just digging a hold to dig a hold and intercepting the water table (and not tapping into a properly installed footing w/ drain) then it's a losing battle. water would be resting on a plane like a piece of paper and if you poke a hole through that paper you're not going to get proper drain down except possibly in that general area.

let us know how it turns out.
 

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Love is only a light switch away. :w00t:
So what you're saying is even the ugly women need to turn the light off in order to find you attractive..........:laughing:

Back on topic, you definately need a collecting system in place that will direct all flow into your "sump". I think everyone else has described this process in one way or another. I picture water is a large group of people running towards a building............if you want them all to fit into a doorway, you have to start funnelling them down sooner than 1ft away from the door or they'll never go where you want them too.
 

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Discussion Starter · #17 ·
I don't gather that the OP has a footing already installed as Williams has described...do you? if you're just digging a hold to dig a hold and intercepting the water table (and not tapping into a properly installed footing w/ drain) then it's a losing battle. water would be resting on a plane like a piece of paper and if you poke a hole through that paper you're not going to get proper drain down except possibly in that general area.

let us know how it turns out.
We'll be tying it into the existing outer formadrain drain tile system that's next to the footers, and back filling with gravel below that to intercept it under the basement.
 
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