Bathroom remodel - interesting find under pre-fab shower

[rhwimmers]

Not sure we're on the same page... Here is a pic of the pvc that goes to the grinder/sump across the basement, probably 15' under ground.

https://photos.app.goo.gl/skWmxgEf93CC27LEA
Here is another view from the top

https://photos.app.goo.gl/b9SMUPEbwYTHY8418
If I put a coupler on this then a PTrap with the drain for shower on the other end of the ptrap, should that drain be flush with the ground, slightly below (like the first picture showing the PVC a couple inches under the concrete), or slightly above ground level.

Depending on the levelness of your basement floor, you could be right. But the dimensions you've provided don't compute.

From your earlier posts/answers, the line into your sanitary sump is 3" and runs about 12 feet from your toilet. While I like to run 3" at 1/4" per foot slope, some codes allow 1/8" per foot. The minimum fittings for a toilet, a street 90 and a toilet flange, measure 5" from the top of the flange to the centerline of the horizonal pipe, or 3 1/4" to the top of the pipe. Using the 1/8" slope, that's 1 1/2" for 12 feet. So that would put the bottom of your toilet about 6 1/2" above the top of the pipe entering your sanitary sump. But that's a LOT of slope for a basement floor!

Sound like you need additional investigation of the piping.

 

[MicEd69]

Oops. I was thinking you were talking about the end that went into the sump. Sorry!

Yes, it looks like you will have a problem if you go forward without putting the P-trap directly below the shower drain. I would either get a shower with an offset drain so you can miss the corrugated drain line, or again, gut that drain line or relocate it under the shower drain line around the trap. And while it would be more work, you could make your own shower base with concrete and tile so it would fit wher you could put the P-trap.

 

[rhwimmers]

Ok I think I FINALLY have a plan. Any thoughts/changes?

https://photos.app.goo.gl/5EVdMfSKDofTyaBR7
I plan to put tile down on the concrete first then the shower pan.
I also got some 4in1 product (think it's basically like a sand material) to put in the hole which should raise the water level up enough to get it in the corrugated pipe to prevent having as much standing water like I do now. It will bury a majority of the plumbing here but I'll be covering the corrugated with nylon so water can still flow where it should. Thoughts?

 

[MicEd69]

That looks good to me.

I am still a little concerned about the toilet pulling the water out of the trap without a vent between the P-trap and the sewer sump. I'd like someone else on this forum to comment on that issue. But the worst thing would be you smelling some sewer smell in the shower that will be resolved by running a couple of cups of water in the shower.

 

[rhwimmers]

Yeah, can't be any worse than it was since there was no ptrap at all before it rarely smelled and no one ever goes downstairs nor uses this bathroom