toilet not draining right

bathroom built as part of addition drainage plumbing in a crawlspace (i.e. accessible). Work done in 2005.

Toilet is a Kohler with an over-sized trap. it sits next to a jacuzzi tub that rarely sees action.

symptoms

1) When toilet is flushed, a loud gurgling noise can be heard through the tub drain.

2) The toilet sometimes has trouble draining and backs up despite it not being, shall I say, abused.

the sinks smell bad fairly often and need to be rinsed with bleach a couple times a year.

Questions:

a) Could the toilet's issues be a result of inappropriate incline on the drain line?
b) is the gurgling in the tub after a toilet flush a sign of improper air trap setup or normal.
c) does the occasional drainage problem, together with the odors indicate possible problems with the vent?

Some questions first. Is this a new problem with the drainage or has it been this way since the remodel? Was the plumbing installed by a plumber or a general contractor? Was the plumbing inspected by the proper authority?

can you get some pics of the plumbing in your crawl? would help us determine if the piping is correct.

problem with drainage has been since construction, though it manifests itself fairly regularly about every quarter. At first I wrote it off to excessive paper, but the regularity of the issue hints at something else. Plumbing was installed by a plumber, and the GC got all appropriate inspections done AFAIK, though they are out of business, and we did not get final closure paperwork, so I can not attest to that. I will try snapping some pics of drainage and vent plumbing in the next 24 hrs.

Marc

Link to photo of drain line and roof vent below.

The toilet is at the far end of the bump out and the drain line runs in a straight line back towards the camera, then takes a 90 degree turn to run into the house to join the main sewer drain. In the basement, it runs around a couple walls with what appears to be a reasonable steady, incline, though I have not measured. The line running under it is the tub drain, which joins it approximately at the turn, which would be in the top left corner of the photo.

Shot of drain line:

Picasa Web Albums - inge plante - Pictures

Shot of the vent on the roof, not too useful unless it is not high enough to vent properly (?) couldn't get up onto the roof to get a shot in line with the roof peak.

Picasa Web Albums - inge plante - Pictures

TIA for any thoughts,

Marc

i don't see a vent for the toilet. this may be the reason your tub is gurgling when the toilet is flushed. also the tub drain is goofy, we cant (build) a pee trap from a bunch of 90s like that not to mention is isent self cleaning and will b a problem down the road. from what i see your plumber was a hack and i would b suprized if that set up passed inspection. do you know the name of the plumbing company who did this work? have you called them about this problem? i would check with your village to see if it was inspected. did your contractor pull a permit? if you had a permit you can track down the inspections.

Thanks for confirming my suspicions. Time to call in a proper plumber to clean up the mess.

Marc

Yeah, that's why I asked about the inspection. I can't see a plumbing inspector passing that work. GCs usually circumvent the inspection process one way or the other to cut corners and save money. Hope it all works out better for you with the new plumber.
Also, that looks like a concentric vent cover for vent on the roof. May be for a furnace or power vent hot water tank, not the plumbing.

I would have to agree with Caduceus on that one .