Haha actually take what I wrote here back about the drain and focus on the shower arm i thought it was the baths causing the problem not the wife's shower at first read. But the idea still helps eliminate possibilities before you go cut some holes. Fill and drain sink, toilet and tub to rule those out. You've got a drop ear at the shower.

First I would reapply plumbers tape and maybe a little pipe dope and reattach the the shower arm. If that doesn't fix it odds are the supply leak is the connect from your shower pipe to that drop ear. That will either be soldered for copper or some sort of pex fitting and you'll have to cut drywall to check.

For drain issues: Fill the tub, tint the water and drain it. Look for that color. Sounds like a waste side leak. I had this problem last year. Bad fitting going from cast iron to PVC and it broke the seal over time. Be glad it's not your kitchen ceiling like mine was.

It's all threaded pipe from what I can see. You cannot just cut galvanized and reconnect with a sharkbite because of the outside diameter. Sure the IPS is all the same but the sharkbite has an ops that is less than galvanized line. Secondly they are not designed for galvanized line.you can get a female 1/2" threaded to sharkbite and screw the thread into your existing line and then convert the rest to copper or pex, but at some point it appears you need a threaded connection along the way. The only way you can cut a pipe and use a sharkbite is on copper or pex.

I think you need a plumber at this point.

The other question here is how are you going to shutoff to make these changes? The t you want to move is below your working shutoff. If this is an apartment I'm not sure you'll be able to do the shutoff further down the line and not affect your neighbors.

You don't have brass. You have galvanized pipe. You can't shark bite galvanized pipe you would need a threaded adapter at some juncture to go from galvanized to another pipe material.

No.

If you break a section you'll need to move further down the line to the next threaded section and attach there.

Also do you need gas line for the dryer or electric hooked up... Not sure if that was included in the cost as well.

Yea I'm siding with the plumbers here. You need a vent and a proper drain and that's the issue. The water supply is not a problem but to drain and vent properly.

To do this the right way you need access behind your cabinets and to cut along studs to run everything behind the wall. It's a fairly big job, 4000 seems a tad high but not out of line. You might be able to save some money by running the water lines yourself.

You could try an oatey sure vent so you don't have to vent outside but you might find that doesn't fully vent your sewer gas and you'll get smells inside.

Not easily. You'd probably want a plumber for that.

As long as your other shutoff above it works there isn't really a need to remove the old one either. I would just leave it be personally.

As long as your other shutoff above it works there isn't really a need to remove the old one either. I would just leave it be personally.

No again I can't see whats coming front hr wall but it appears to be a threaded end. You will need a threaded compression valve to twist into the existing pipe, compression only works on copper.

I recommend shopping for parts through supplyhouse.com. you can even call and they will take you through what you'll need.

The stub coming from the wall being threaded will require a female end quarter stop to 3/8 threaded end for your T to attach your water line to fridge and the cold water for your faucet mixer.

You can't shark bite galvanized pipe.

Pex is the easiest solution you can get an adapter for 1/2 threaded pipe and then use shark bite fittings or get pex crimp rings and the tool to tighten them. Copper would require you to solder at some juncture. But again I'd need to see your whole system to give you the best options. YouTube is your friend. Plenty of videos on all the connectors and ways to accomplish this.

Yea I think they used black iron 🤣. Definitely not done by a plumber.

All of that threaded pipe that is your water line appears to be galvanized. Although from the picture it actually looks like black iron gas pipe.

If you don't own the house just remove the t on the cold side and get a new threaded T for the hot side.

Yes you would just need to remove the t and put the rest of that side back together without it. Use Teflon tape and probably have some pipe dope in case you struggle to get a leak tight seal.

Personally this would be a great opportunity to just run some pex since that galvanized line starts to corrode inside over time.

Not sure what the rest of your system looks like but if you can take all of that out and get back to copper you'd be doing yourself a favor long term.

Do you have dishwasher hooked into cold side as well?

I'd just a t to the hot side moving the dishwasher over and that would solve the problem.

Alternatively you could replace the single shutoff valve and get a split shutoff valve for one side giving you two connection points.

That's quite the setup down there. Two sets of shutoffs for each water line and copper drains. Is there some galvanized line down there as well?

Just read this and calm down. You are reciting lies from big oil lobbyists at alarming rates. Motortrend covered all of this. https://www.motortrend.com/features/truth-about-electric-cars-ad-why-you-are-being-lied-to/amp/