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Old 12-06-2010, 03:53 PM   #1
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Sump pump float height


I'm struggling with a wet basement and need to verify if my sump pump is kicking on and off at the correct water height, or if changing it will help.

I have a crudely dug sump hole with PVC basin, submersible pump and tethered switch. There is gravel in the bottom of my PVC basin upon which the pump sits, 17" below the basin top. Not sure how high the tethered switch floats from the pump - maybe 6"-8".

I've read you want the pump set to never let the water get past 1 or 2 inches over the top of the foundation drain pipe entering your sump. Problem is I don't have drain pipes as it is an after the fact dug sump hole. All I have is gravel outside my basin through which water seeps.

So how do I figure my correct sump pump float turn on/off height?

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Old 12-06-2010, 05:12 PM   #2
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Sump pump float height


In your case, I would set the float to turn the pump on when the water reaches 4 inches or so below the level of your basement. The pump should turn off when the water reaches approximately 6 inches above the bottom of the sump pit.

Given that you have no piping carrying water to the sump, it may not be possible for the sump pump to keep the basement dry. Normally there is a perimeter drain around the house with perforated pipe that collects groundwater, and maintains the groundwater level at least six inches below the elevation of the basement. By your description, you simply have a hole in the ground, with some undefined amount of gravel adjacent to the hole, so you may not be able to drain groundwater effectively from beneath the slab. Repair would require installation of an effective perimeter drain, either inside or outside the basement.

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Old 12-07-2010, 12:18 PM   #3
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Sump pump float height


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Originally Posted by Daniel Holzman View Post
Given that you have no piping carrying water to the sump, it may not be possible for the sump pump to keep the basement dry. Normally there is a perimeter drain around the house with perforated pipe that collects groundwater, and maintains the groundwater level at least six inches below the elevation of the basement. By your description, you simply have a hole in the ground, with some undefined amount of gravel adjacent to the hole, so you may not be able to drain groundwater effectively from beneath the slab. Repair would require installation of an effective perimeter drain, either inside or outside the basement.
Thanks Daniel. You are correct, it is just a hole dug in the ground. And that is what I fear most, that this sump will not be enough.

However, I do have some suspicions and some evidence the basement has a perimeter drain. Can a sump be retrofitted to perimeter drain after the fact?

Would another sump hole place in a key spot help?
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Old 12-07-2010, 01:21 PM   #4
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Sump pump float height


Quote:
Would another sump hole place in a key spot help?
Does all the water collect in the sump hole you have now,..??

I'd think enlarging the existing 1 would give more of a reservoir for the pump to move during cycles, lessenin' the number of cycles...
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Old 12-07-2010, 03:34 PM   #5
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Sump pump float height


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Does all the water collect in the sump hole you have now,..??

I'd think enlarging the existing 1 would give more of a reservoir for the pump to move during cycles, lessenin' the number of cycles...
Unfortunately not.

I live on a hill that descends south to north, and the sump hole was dug on the north east corner of the basement. This may have been done because they stupidly finished the basement and then had to find a place for the sump hole.

To make matters worse, on the northwest corner they put in a floor drain that I just recently discovered appears to connects to the outside footer drain. Not sure why, other than the footer eventually went somewhere downhill away from the house into maybe a dry well, but now is plugged. I literally get water bubbling (no kidding) up from that drain during heavy rain. Naturally this will make a great secondary sump hole, and I plan to put it in.

Right now most of the water is coming in from that silly drain, and to a much lesser extent the southeast, and east side of the basement. Despite my plan to put in a sump hole where the floor drain is, I am skeptical it will help the southeast, and east side of the basement.

So I am wondering if lower the height of my sump pump will help my southeast and east side of the basement.
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Old 12-07-2010, 04:53 PM   #6
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Sump pump float height


If you do in fact have a perimeter drain, you can certainly tie the sump in to the drain. You need to verify that the drain extends around the entire house, and is adequately deep. If so, you enlarge the sump pit, and connect the perimeter drain piping into the pit. My question would be if the builder went to the trouble to install a perimeter drain, where did they tie the drain to? It seems odd at best to build a perimeter drain and not connect it to daylight or a sump pit.
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Old 12-07-2010, 05:47 PM   #7
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Sump pump float height


Quote:
Originally Posted by dac122 View Post
I'm struggling with a wet basement and need to verify if my sump pump is kicking on and off at the correct water height, or if changing it will help.

I have a crudely dug sump hole with PVC basin, submersible pump and tethered switch. There is gravel in the bottom of my PVC basin upon which the pump sits, 17" below the basin top. Not sure how high the tethered switch floats from the pump - maybe 6"-8".

I've read you want the pump set to never let the water get past 1 or 2 inches over the top of the foundation drain pipe entering your sump. Problem is I don't have drain pipes as it is an after the fact dug sump hole. All I have is gravel outside my basin through which water seeps.

So how do I figure my correct sump pump float turn on/off height?

I wouldn't get too set on adjusting the pump cycle off of the inlets anyway. We typically drop the last few feet of the pipes drastically into the crock, which gives a false sense of water levels around the foundation. Like Dan said above, 4" before basement floor minimum, IMO 6-8" is even better. But, you need to make sure that you're not short-cycling the pump by doing this as well.

Quote:
Originally Posted by Daniel Holzman View Post
If you do in fact have a perimeter drain, you can certainly tie the sump in to the drain. You need to verify that the drain extends around the entire house, and is adequately deep. If so, you enlarge the sump pit, and connect the perimeter drain piping into the pit. My question would be if the builder went to the trouble to install a perimeter drain, where did they tie the drain to? It seems odd at best to build a perimeter drain and not connect it to daylight or a sump pit.
I agree with your thinking Dan but I think, at least from what I'm reading from the OP, that the entire draintile system lead to daylight originally, and got damaged and aborted along the way.
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Old 12-07-2010, 06:58 PM   #8
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Sump pump float height


As I recommended elsewhere, you might want to consider buying a transfer pump just in case.

http://www.amazon.com/gp/product/B00...=ATVPDKIKX0DER
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Old 12-08-2010, 08:47 AM   #9
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Sump pump float height


Daniel,

I too am wondering why would a builder go to the trouble to install a perimeter drain and not connect it to daylight or a sump pit. I actually have the house plans and tried contacting the original company but they say they have long since disposed of any plans. More confusing is I bought the house from the original owner so I am very confused about why they did what they did. All I can think of is they ignored the problem and went forward with adding a deck and finished basement, but then discovered they had a problem; and instead of dealing with it head on they chipped around the edges.

Do you know of any way to verify a perimeter drain system exists short of excavating? I know I have it on one side - just can't imagine why they wouldn't put it on the other side.

jomama45,

Thanks for the tip on most drain pipes. Agreed I want to be sure I do not short cycle. It appears the pump was set a little high in the sump crock, so I should be able to lower it. It sounds like the objective is to make sure you have a large volume in the crock before pumping to prevent short cycling.

handy man88,

Thanks I have an auxiliary submersible pump with garden hose connection. It has already earned its keep.

All,

Once issue I have read with dug pits is if you lower the sump hole too much you could begin washing out your foundation gravel. Ever hear of this concern or a case where this happened?

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