Sewage ejector-water table problem

[rockosani]

Hi... I purchased a Little Giant Sewage Ejector Simplex Package... and that was the easy part. I'm trying to add a full bath in a basement that is about 4' below grade but when I dug the hole for the container... about 27" down... I hit water. Now I have about 8" of water in the hole and it's all but impossible to get the container to sit properly since it now wants to float. I have lots of ideas... none seem very good and I was hoping you may have a suggestion for the do-it-yourselfer.

Can I drill a few holes in it to balance the pressure by letting the water table rise to an equal height in the tank? I'm not sure how that effects the effluent in the tank but would a back-flow valve work to let the water in and not the effluent out? I doubt that the water would be high enough to trigger the pump but I'm at a loss on what to do in the event we get some heavy rain, the table rises a little more and my poop pump is bobbing up & down in the hole with some pipes hanging out. Lastly, would it make sense to drop the tank in the hole, fill it with water, apply some concrete anchors to the floor and then pump it out?

If none of those ideas work I'm open to suggestions and know answering this stuff is probably not why you go to the office but anything would help. Thanks

 

[Toolaholic]

do not drill holes in box effulant will leach under slab!

i would cut a 12' dia hole in concrete 1 foot away and 30" deep. set a small sump pump in this in this. and pump the water up and out for several days.
now fill ejector tank with water ,set in concrete. xtra insurance would be threaded rod [2] coulped to concrete anchors. after 3 days remove pump and fill in hole with concrete.

 

[Sponsor]

 

[rockosani]

Thanks... hope you meant a 12" hole

The hole filled with 8" of water in about 10 minutes so what's the chance I could pump it down for any length of time to do some concrete? I don't mean to be dense here but doesn't water seek it's own level fairly fast?

 

[Master Plumber Mark]

You Got Some Fun Ahead Of You

do not drill holes in that sewage pit!!!!!!

eventually it will burn that pump out
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I tangled with one like this back in 1993

it was not fun cause we still had to dig that hole deep enough

to make the system work.. It turned out we were actually digging

on an old river bed and clear water was actually passing

under the basement floor we were digging.into

... It was mean, mean ,, mean


What you can do is dig a larger hole and put that pump in to

help pump out the excess water while you are digging down

into the muck.... thats lots of fun,

Easier yet, you can just keep pumping the thing out '

over and over while you are digging it deeper

till you get it deep enough

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once you get it deep enough the only way you can make it work

is simply to fill up the pit with water so it cant bob up out of the hole.


you got to fill up the barell up to the drainhole and it wont come up


then to get the concrete to work, you got to get some 2x4 studs

and literally hold that pit down in place.....


put the pit in the hole , fillit up with water,

then lay a 2x4 flat across the pit

then cut a stud to fit between the flat 2x4 and the ceiling joysts above you.


if you make it a tight fit it aint going anywhere....

then just do the plumbing and then cement the pit into place before it

gets away from you.... once you get the pipe to the plumbing system in

place and put cement over it it probably wont ever move again , once it is set up

the one we installed in 93 still has 2 2x4s across the top and 2 studs going up to the ceiling......

it hasnt moved yet.

 

[rockosani]

Good idea...

Thanks... I think that'll work since I can't force more gravity over it the 2x4's can replace it. I think this whole valley is nothing more than a back-filled river bed. I guess I don't need concrete under it... just around the sides? I was thinking of cutting a metal trash can in half so that it was above the water table, dropping it in the hole, fill it with water, pump out around the outside and then drop in the concrete around it. I could then drop in the liner and fill the rest with concrete but the water comes in about as fast as I pump it out and I didn't want to add a pedestal because it would probably never shut off. The problem I was also having is that the liner has a floor flange around the top but I guess I can jack out some more floor. Thanks again!

 

[Master Plumber Mark]

floor flange

all you got to do it get it deep enough to get
the plumbing to work.....

fili it backin with dirt and then a lot of sand mix type
finishing concrete too....


the lip does not have to be flush with the floor. either

IN fact its better with it above the floor because

it keeps water from settling on the sealed lid and rusting

it out....its better for any basement water to go to the sump pit

and not get the chance to settle on that lid,
then you got to sop it up all the time...

the one we installed was at least 3 inches above the floor....

just deep enough to work no more than what was needed.

its all in the mechanical room and really does not matter.

 

[rockosani]

A river runs under here also...

This one will be in a room also so looks don't count. Can I add a p-trap with a backflow to use my effluent pit as a basement sump also or would you recommend a seperate pit for that... I have had nothing but water problems here because of a high table, all the downspouts ended at the foundation and the grades slopped toward the house. I have corrected everything except a secuity blanket if a little more seeps in. The liner for the sewage pit is a hard plastic with a foam lined lid so rust isn't an issue. I'll plumb it as high in the hole as I can and that should help. Thanks!

 

[Master Plumber Mark]

separate pit

While you are digging the whole place up its best

to put a pit right next to the sewage pump and

course make it lower and flush to the floor

you should not mix the sewage pit water with the

seepage water .. it wont pass code in our area

 

[rockosani]

Lower?

I was thinking of a shallow pit... like 24"... to stay above the water table and just catch any floor water that may filter in. If I put it lower and flush wouldn't it constantly receive water from the table and never stop running? If I set the float higher I still have a pit of wet and was thinking an open pit would work but it sounds like you're recommending a deep covered one... is that right?

 

[Master Plumber Mark]

24 Inch

It all depends on what you want to accomplish

If you are on literally an aquafir and their is always water down there

its probably best not to dig down too far....


what I meant by lower, you want that pit to be flush or slightly lower

than the floor level. everything should just natrually flow into it....


a 24inch pit would work great... with a bunch of small holes drilled in it

from the top down to about 5 inches up from the bottom would

work real fine to keep the water table at bay.
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If teh 24 inch is too deep by makeing it flush with the floor,

just shave off a few inches of the plastic top till you find the right
spot that works best
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thats your best route , you arent going to win against the water

but you can at least get a draw or stalemate.

 

[Toolaholic]

they pour dams under water

concrete sets up under water at same cure rate. temp .sump pump in hole close by while you pour and cure is a good idea though. is tank plastic or metal. liberty uses plastic

 

[rockosani]

The water is flowing...

I’m on an aquifer and it’s a sandy soil… dirt, clay then sand… that began eroding back under the clay since the water is moving. I filled the voids with concrete from the floor removal and that seems to have stopped the erosion. I think I know what to do to get my poly basin in the ground… and keep it there. I’ll backfill, pour some concrete and brace it in place, buy another house on a hill and move ASAP. I’ll add a shallow sump pit near it for seepage. With about 6†of water to deal with I’ll set the switch on the pump to a higher level and use the effluent as ballast. Thanks for the great advice and it’s no surprise that others have found a surprise when digging a hole… other than a boulder or a cemetery… water is the worst. Thanks for all the help and advice... now on to the dig site.

 

[hj]

pit

From all the discussion, it seems you may be making this job more difficult than it should be. If the ground is not flowing sand, like quicksand, so that you cannot dig the hole deep enough and fast enough, then just dig the hole put the pit in place and then add about 8" of water in the bottom of it to sink it. rotate it into position, and then add some more water and backfill dirt around it. Once I had to sink a 60" diameter by 60" deep cast iron basin into ground that had a water table about 10" below the floor and the sand flowed just like water. We had to build a cofferdam to hold back the sand and then float the basin into position, and finally fill it with water to sink it. Then we had to install "tie downs" to keep it from floating out of the floor once the pumps started operating and emptying it during use.

 

[rockosani]

Pit2

I'm sure I was making more of it than I should but we're not all experienced plumbers... though I do know enough about it to have passed at least oneinspection. However, when I hit moving sand I was more concerned with that than I was clear enough to see that I could lift the basin a bit higher. I just kept reading those directions about digging a 30" and place lip of basin on floor grade while I was watching the erosion create a hole twice the size of the one I dug at the bottom in about 1/2 hour I over-reacted. Anyway, thanks for all the good advice.