What is this for?

Newbie house owner here. What is this pipe for off the side of my house? It looks like it became disconnected. I’m assuming I need to fix it and re-connect it?

Where can I get 3 way copper corner fittings?

I'm trying to find this but a yorkshire fitting made out of copper, doesn't seem like they make them

Can I cap and abandon this old cast drain pipe?

We are adding a shower to the basement bathroom and thought the pipe going to the toilet and sink was updated with the rest of the pipes. It wasn't and runs parallel to the new abs which goes to the main stack and upstairs toilet. The cast must connect to the abs somewhere to the left, as I know it's ABS further down the line and where it exits the house. Can I cap and abandon the old cast next to the cleanout and continue the new abs to the right and connect the basement toilet, shower and sink to the ABS? TIA

Should I remove the plate behind the black mixer cup?

The top screw (encircled in blue) is stripped. Before I go in there with drill bits and screw extractors and ATTEMPT to remvoe the broken off screw, I was wondering if I could easily remove the black mixer cup and the plate behind it (encircled in red). Removing this plate would give me better access to the screw. And if in fact, the plate can be easily removed by unscrewing the two large screws, do I need to shut the water off prior to doing this? I am just a home owner DIY'ing, with limited plumbing knowledge, so any pointers would help. Thanks! Note: The screw was stripped by the previous home owner

I can’t tell if it’s water is coming in from the wall or a tank/softener.

Any suggestions on how to tell?

CPVC threaded fitting failure - how did this happen. 30-50 psi loop in solar hot water system. CPVC threaded into Cu. Just burst all of a sudden. Good I was home; river coming through the ceiling fixtures. Replaced with SharkBite. Other thoughts?

Any advice on how to get out these horribly rusted screws?

I sprayed WD40 on it and tried to get them out with no luck. Maybe I need to call a professional.

Any advice on how to get out these horribly rusted screws?

I sprayed WD40 on it and tried to get them out with no luck. Maybe I need to call a professional.

We’ve been without water for a couple days due to it being a holiday weekend when this started leaking. What kind of financial damage are we looking at for something this small and easy to access?

2 handle shower valve with set screw from inside fell off. How to remove

You can see the screw on the inside but the backside of this shows no way to get to a set screw. Any ideas ?

Submersible sewage pump, fall on send pipe?

Does the Send line to the septic tank need fall like normal plumbing? I'm wondering if I can get away with running with minimal fall because it's pumping and not relying on gravity. I'm in Ontario, Canada.