Is this the problem?

Hey guys! Please help lol! I don’t intend to make any repairs myself but I need some advice to figure out what to do before calling in a professional. (Money is tight) The toilet was flushed in our in law apartment and the shower gurgled, now it stinks in the bathroom. I went downstairs to pretend that I knew what to do and ended up just looking at all the pipes. I found this coupling that looks.. weird. I think I know the answer but.. Is this a problem? Is that poop?? 😱

Any idea what model this is?

A small plastic piece broke and I want to order a new so I can swap it out and not have to tear out drywall.

Here is my proposed setup for a new bathroom, please roast me or offer advice

for whatever it’s worth, it will be slab on grade new construction in SoCal. I’m not a plumber by trade - any glaring errors here?

Why was this pipe left uncovered and how do I cover it?

Pipe above in red has been left exposed, why would this have happened and how do I cover it? When unblocking the main drain in the pic, the sewage was blowing up the red circled pipe. Total novice here would love some advice. Original post here: https://reddit.com/r/askaplumber/s/yMcSJAn0qi

Quick question which one is the Overflow tube?

Can anybody tell me the name of this piece so I can order another one?

I have a slow drip coming from this part of my toilet and I’m pretty sure it’s just that the piece isn’t tight enough or broken. So can anyone tell me what it’s called, I haven’t found it online

Cast Iron drain pipe is failing, how effed am I?

Going to get some bids on replacement/lining and was interested in your opinion on the subject. Live in the Pacific NW, 1960's mid mod with 1.5 baths and a Kitchen all along the back wall of the house.

How do I fix this leaky shower faucet?

Shower drain

I have one of these in my shower and bathroom sink. You click it to plug the tub and when you want it to drain, you press it again and it pops up. The one in my shower is currently busted and is stuck in the "down" position. I unscrewed the metal top and removed the black plastic piece so it will drain (I only have 1 shower). Is this something that I could replace or should I call a plumber? I am a first time homeowner and somewhat handy, but don't want to really mess up my shower.

Old radiator bleed valve

Hi all, looking for some advice if you're able to help. I bleed my rads about once a year but there is a radiator I've got that I've not been able to find the bleed valve....until now. I saw people saying that it might be on the top at the back so I ran my hand along the back and sure enough I found it. I've tried using my radiator key on it but it doesn't fit on. This valve seems to be circular whereas my radiator bleed key is the more conventional squared off slot. Am I going mad or is this valve circular and if so is there a word for the key I'm supposed to use because thus far I've not been able to find it online. Thanks

The Loopty-Loo

I couldn’t believe my eyes.