How to determine if you have a p-trap in basement slab

[MikeKenmore]

i'm remodeling my basement right now. a few weeks ago i removed a shower that was in our bathroom down there. for the shower drain, there was a piece of ABS which simply slid down from the shower pan into the concrete floor where there is another piece of drain pipe that is surrounded by 4" (i think) corrugated plastic pipe.

from what i can tell there was no positive connection or a tight fitting joint. but, i didn't look very closely since i was mistakenly not thinking about the next steps. as far as i know, the previous shower worked fine enough (we hadn't used it since moving in)

now, i'm wondering what lays below my slab. from what i can tell, the plumbing is original (1979 construction) so i would like to think there's a p-trap buried below my slab. is there a good way for me to determine this?

also, is using the corrugated pipe a standard method for rough-in?

i'm very inexperienced with plumbing, so if you can elaborate in your responses, i would appreciate it.
thanks

 

[Terry]

A p-trap holds water. So if you shine a light down there, you should see water. No water and maybe something got left out.
Corrugated piping isn't done for waste lines. Sometime on a slab rough, the p-traps were left off until the bathroom was finished off. Until the walls are up, and the pan or tub is purchased, there's no sense in trying to be too perfect. Perfect is done when you're in the final stages.

 

[Sponsor]

 

[Dj2]

If you are planning a new shower/tub, it would be a good idea to verify that there is a trap.

One way to find out if there is a trap (if you don't see standing water in the drain), is to cut the concrete around the drain and dig deep enough to see where the drain turns horizontal.

This might be more than you can chew, in which case a plumber may help.

 

[JRC3]

Was the bathroom original to the house being built or added afterwards? Do you have a sump/sump pump? If no. do you have a foundation drain that drains to daylight? I'd continuously run soapy water through the shower and check either the sump or daylight drain for suds. If you have a sump basin/pump, does it stink? When I've seen showers and such (not toilets) drain into a sump the soap or something tends to get pretty foul. In addition I would also check the main drain clean-out for water flow.

1. Check sump or foundation drain.
2. Check main drain clean-out for water when shower only is running.
3. Have a plumber push a camera through to see what's going on...But be prepared for the possible bad news and costly results.


As a second thought you could pour a bottle or two of red food dye down the drain as you running the water.

 

[MikeKenmore]

If you are planning a new shower/tub, it would be a good idea to verify that there is a trap.

One way to find out if there is a trap (if you don't see standing water in the drain), is to cut the concrete around the drain and dig deep enough to see where the drain turns horizontal.

This might be more than you can chew, in which case a plumber may help.

i wish i had taken some pictures before covering the slab with insulation and 3/4" subfloor, but around the corrugated pipe and ABS pipe were sawcut lines. the sawcut was in the shape of a rectangle around the pipes. then, it looked like they tried to bust out the concrete with a sledge hammer, only getting a few chunks to come out. what happened after that is unknown to me. so, it's hard to say what the whole history is. perhaps some previous owner decided there was either no p-trap and they were going to fix it, or that the location of the drain wasn't where they wanted it. i measured it to be 16" off the wall. my ideal would've been 18" so i could center the drain on a 36" wide shower.

we did not smell anything foul with the old shower in place.

my preference is not to cut out more floor and screw around in there (of course!).

 

[MikeKenmore]

Was the bathroom original to the house being built or added afterwards? Do you have a sump/sump pump? If no. do you have a foundation drain that drains to daylight? I'd continuously run soapy water through the shower and check either the sump or daylight drain for suds. If you have a sump basin/pump, does it stink? When I've seen showers and such (not toilets) drain into a sump the soap or something tends to get pretty foul. In addition I would also check the main drain clean-out for water flow.

1. Check sump or foundation drain.
2. Check main drain clean-out for water when shower only is running.
3. Have a plumber push a camera through to see what's going on...But be prepared for the possible bad news and costly results.


As a second thought you could pour a bottle or two of red food dye down the drain as you running the water.

i think the work is original.

there is no sump pump.

i have never seen a drain that drains to daylight in my yard. outside of the house, about 20 feet from where this downstairs bathroom is located, is a sewer cleanout hatch (i assume - i haven't looked inside).

how does the main drain cleanout typically work? if i pop open the box, is there a screw cap i can remove and watch water run through?

what would the test best for seeing if this shower drain works properly?

 

[JRC3]

Do you have a septic or sewer? Either way there should be a cleanout, being a basement I would suspect it is in the floor somewhere. If you have sewer it's probably near the wall where your tap water enters. If septic it should be towards your tank.

Probably looks like this: https://terrylove.com/forums/index.php?attachments/dsc01155-jpg.5082/

Could look like this but all PVC: http://rochester.propertysourceonline.com/blog/wp-content/uploads/2012/04/PVC-Drain.jpg

Now, with that said, if the cleanout is NOT in the floor and it come through a basement wall, I would almost bet the shower does not flow in to it: http://www.fairfield-city.org/images/ww/Basement Cleanout.JPG

I would check inside the "hatch". My guess that may be a water meter or who knows what. Also I would think you's have some sort of foundation drainage. Who knows, Things may be done way different in Washington than in OH.

 

[MikeKenmore]

water is city water.

there's a few cleanouts that i see in the vicinity of this bathroom. the shower drain, however, is at the lowest end of the main drain (based on how the sewer line outside the house runs and the local topography). there's a cleanout for the upstairs kitchen sink line. then one for the washer line. then one for the downstairs sink which is a few feet from the shower (with a toilet in between). i think the downstairs sink cleanout also serves the two upstairs bathrooms directly above.

our water meters are at the start of our shared driveway (there are 4 meters for 4 houses) about 300ft away.

 

[JRC3]

There should be a big cleanout, like at least 3" or 4" round.

If there is a toilet then there is definitely a sewer line below the basement floor. Not saying the tub is tied into it, but that's one thing you;re trying to figure out. I'm thinking of one house in particular that had a toilet but the vanity and shower drained into the sump.

One thing I would try would be a shop vac. Put the hose on the exhaust port so it blows (this is my preferred way of emptying P traps to take them apart). When you push the hose end and seal it around the drain the vac motor will be load with resistance and then should free up in like a second or two as the water is pushed from the trap.

Also try to seal the hose to the shower drain by pushing it in or sealing it with a rag and your hands. You may need a second person. Blow air into the drain and relieve quickly a few times or just turn the vac on and off. (remember, you blowing not sucking) Look to see if the water in the toilet bowl moves a little.

 

[MikeKenmore]

thanks for the procedure. right now (and for the foreseeable month +) i have no toilet or sink in that room. it's just flooring and plumbing stub-ins. would i still be able to do the procedure you mentioned?

i have to imagine the drain line connects. it's not more than 30" away and is more or less a direct line to the box outside. i will take a closer look sometime soon to see if there's another cleanout on the other side of the shower wall (garage)

 

[JRC3]

i have no toilet or sink in that room. it's just flooring and plumbing stub-ins. would i still be able to do the procedure you mentioned?

Even better, just listen for the vacuum's motor and suction noise from the uncovered toilet flange.