High Water Table

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by CanadianSal, Sep 13, 2019 at 6:25 PM.

  1. CanadianSal

    CanadianSal New Member

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    May 2, 2019
    Location:
    ontario
    I have a septic pit in the basement and i am about to install a basin. This is a new installation.
    During the winter months the pit was constantly filling up with water - I actually installed a temporary sump pump and it was going every 1/2 hour or so. The pit has remained dry all summer. I am assuning that this is a high water table issue and i wil come back in the winter.

    Now I am about to install the septic basin and pump, and was wondering what would happen to the water in the winter. Where will it go? So I consider extending the Septic Pit and install a sump pump outside the septic tank?
     
  2. kreemoweet

    kreemoweet In the Trades

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    Location:
    Seattle. WA
    The water won't go anywhere. It'll just rise to the normal winter water table level and surround the
    basin. It can exert a pretty fair amount of bouyant force on the basin, which might be troublesome.
     
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  4. Reach4

    Reach4 Well-Known Member

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    Septic, as in that is where the toilet flushes into?
     
  5. CanadianSal

    CanadianSal New Member

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    ontario
    Thats is correct.
     
  6. CanadianSal

    CanadianSal New Member

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    Thanks. Should I consider putting a sump pump adjacent to the Sewage basin? I currently have a sump pump about about 15 feet away.
     
  7. Reach4

    Reach4 Well-Known Member

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    Location:
    IL
    I presume that you do not have a city sewer.
    When you have a septic basin in the basement, it should be sealed, and a 2 inch vent should run to the roof. The sewage gets pumped up and joins the pipe going to the septic tank outside.

    Here are some thoughts not based on experience. For a sump pit for ground water, the ground water still needs a place to go. It can sometimes be piped to a "dry well" -- an outdoor pit with gravel in a lower part of the yard. Is there a low part of the yard, away from the basement, where you could put that ground water? If you keep the pipe sloped as it goes out thru the cold, it should not freeze on the way out. If the water stands in a low spot, it could plug the pipe. You may want to put a vacuum breaker on the high part of the pipe indoors so that it can let the water get carried out by gravity. I

    QUOTE="CanadianSal, post: 600654, member: 89240"]Thanks. Should I consider putting a sump pump adjacent to the Sewage basin? I currently have a sump pump about about 15 feet away.[/QUOTE]
    If that is where the water creeps in, I think yes, another sump pit in the basement would be a good idea. I think putting holes in just the upper part of the sump liner to admit ground water is good. I am not a pro.
     
  8. CanadianSal

    CanadianSal New Member

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    ontario
    If that is where the water creeps in, I think yes, another sump pit in the basement would be a good idea. I think putting holes in just the upper part of the sump liner to admit ground water is good. I am not a pro.[/QUOTE]


    So how do I pipe the water- do I install sump basin next to the sewage basin? The sewage basin is 18X30 and I will seal it and it will be surrounded by concrete. Do I just jack hammer the current pit and make it double the size? this way the water will collect in the second pit? Does any of this makes sense?
    I am on a septic system - no sewer.
     
  9. Reach4

    Reach4 Well-Known Member

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    Location:
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    I would consider keeping both pits with their own pumps.

    I would not put it right next to the sewage pit so that further leaks would not go right into the new sump. I don't know the best way to seal the sewage pit, but sealing that is important. If you cannot do that, maybe have the septic pit replaced.

    I would put the new sump pit at a spot where ground water appears now during wet times. I would use a nice new plastic sump. I might use a pit designed for sewage, because it may be stronger. But I would not seal the lid probably. I would drill 3/16 holes at about the level of the gravel under the concrete. Let in water, but not gravel. Note there is a difference of opinion as to whether to also drill low holes in that pit. Put pea gravel around the outside of the new pit, especially outside where there will be holes.
     
  10. CanadianSal

    CanadianSal New Member

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    Thanks you. The ground water is filling up the sewage/septic pit. So its the same spot.
     
  11. Reach4

    Reach4 Well-Known Member

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    If water can leak in, sewage can leak out.

    However it is also possible that the water enters that pit via a pipe rather than breaching the walls of the pit.
     
  12. CanadianSal

    CanadianSal New Member

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    ontario
    Just to clarify. I have an empty pit currently - just a hole in the ground. (Sorry I might be useing the wrong words). I am now in the proces of putting the basin into the pit. I was not planning to put holes in the basin as I was made to understand that is not correct.
    So the concern is - once the water starts to rise - and I have now put a basin in the bit, the water will be displaced, and how do I get rid of it - or should I worry about it?

    A plumber told me that it will eventually make its way to the current sump basin which is about 15 feet away (water finds its way). He also said that we can look at this at a later date (after the sewage bin is installed). I am thinking of addressing both at the same time. I am not sure if that is feasible.
     
  13. Reach4

    Reach4 Well-Known Member

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    We are talking about the sump pit for ground water -- not the septic pit.

    How would water get into the basin -- from the floor above? Anyway, you will need to have the basin anchored. It will have considerable force up trying to float up. So after you place the pea gravel, you hold the basin with mortar. I was picturing a second sump pump in the new basin. That also gives you some redundancy for if the first sump pump fails.
     
  14. CanadianSal

    CanadianSal New Member

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    Location:
    ontario
    Thanks for your advice - I might be out of my league here, but I am still unsure of how to proceed. @Reach4 - thanks for engaging in this.
    I am uploading a picture - hopefully this helps to clarify my concern. The picture shows the pit - the inlet from the toilet/shower/sink is on the right - ths is not hooked up as yet - so brand new.
    The water seems to be seeping in from below the floor - see the black line. The water usually disappears by itself - my observation over the last 2 years. This year I put in a temporary sump pump and it was going a lot - so this is a lot of water. Ignore the tub - I placed that it there to hold my temporary pump.
    So I will be putting the basin in this pit. Hopefully this helps. I have not had an issue with water on the floor for the last 8 years since I bought the house. This pit must have been filling up and emptying itself for the past 30+ years. I only found this pit about 2 years ago - it was concreted over.
     

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  15. Reach4

    Reach4 Well-Known Member

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    That is not a suitable pit for toilet waste, I think.
     
  16. CanadianSal

    CanadianSal New Member

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    ontario
    Why do you think so? Appreciate your thiughts.
    The plan is to bury this in this in the pit. [​IMG]
     
  17. Reach4

    Reach4 Well-Known Member

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    Location:
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    That would make it suitable if you run the sewage into the side port. You need the 2 inch vent hole in the top as well as a grinder pump exit pipe. The vent connects to an outside vent, usually through the roof. An AAV is not suitable for that.

    The pit in your picture looks surprisingly (unbelievably) clean for something that has been receiving toilet waste.
     
  18. CanadianSal

    CanadianSal New Member

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    May 2, 2019
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    ontario
    its brand new - this has never been used - its a new install. Yes there are 2 hles on the lod - one for vent and one for the pump.
     
  19. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Retired Systems engineer for defense industry.
    Location:
    New England
    You definitely don't want to allow ground water into your sewage ejector pit basin. You don't want to be dealing with its pump any more often than necessary, and if it needs to move ground water in addition to waste, it will need to run much more frequently and fail that much sooner. And, if groundwater can get it, it is possible sewage could get out, making a mess of the soil in the area that would be difficult to fix later.

    The house I grew up in was 1/4-mile or so from the town's spring fed water supply. The water table was quite high, and except maybe in the middle of the summer, the system would run fairly frequently to move water out.

    If the hole where you want to put the new basin is full of groundwater, getting the new tank in place can be a pain as it will float. You may need to rent a pump to pull enough out, do the plumbing connections, and back fill it so it will stay in place. If not anchored, it may pop up, and could end up putting a lot of strain on the fittings as well. This is not a particularly good situation!

    What you need is someone likely more knowledgeable to help you resolve this with something that will work for you in this situation. You may not find it on a webpage.
     
    CanadianSal likes this.
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