How to figure out confusing plumbing and water flow directions

“Before I make my final cuts and glue everything, does this look acceptable? First time ever doing plumbing work. Open to all suggestions!”source ↗

“now I can’t connect two pipes because they are not close enough to tighten together.”source ↗

“Thanks for popping in and telling me im wrong but refusing to be helpful!”source ↗

“I'm adding a bathroom in my basement and need to raise my shower for drainage- this would be a great option to save space but im skeptical since ive never seen one before.”source ↗

“Someone decided they wanted a double vanity without opening the wall and doing it properly. Between the s trap and the tee accepting flow from both directions this is bound to give you some troubles.”source ↗

“I am remodeling our bathroom and am driving myself crazy trying to figure out how/why they have the bathtub plumbed the way they do.”source ↗

“I am struggling to understand if this is a old-timer way of making something work or if I need to completely redo it.”source ↗

“I wouldn’t, looks like a nightmare to snake through”source ↗

“I believe what I'm looking at here is an S-trap from every post l've seen on this subreddit. But I'm not 100% sure.”source ↗

“Would the water flow on this system be from right to left?”source ↗

“Does the red lever shut off water "after" the pressure tank receives it, and is this the proper way, or should it have been before the pressure tank?”source ↗

“All my pipes in the crawl space are covered in spray foam so I can't trace the path they take down there.”source ↗

“My initial thought was some type of water softener. But it’s before the sediment filter so that doesn’t make sense.”source ↗

“Manual said to drill on a vertical section above a p-trap. I'm a little confused on where I can do it.”source ↗

“I tried but it won’t because that part is curved and that’s the most it will go normally. If I push it with extreme force, it will then be too far in to be tightened with the screw cap as it won’t be flush with the screw cap anymore. At the same time, it still wouldn’t be pushed in enough for the pipes to meet together.”source ↗

“It’s definitely all the way in. If I cut it, wouldn’t that mean it still wouldn’t be able to go in because it is a curved piece and also it would be missing that round piece at the end?”source ↗

“I’m sorry what’s wrong with this?”source ↗

“Is it okay to replace this sanitary tee with a sanitary cross for a laundry tub drain?”source ↗

“I am adding a shower on the right. Can I simply tie into this 3” drain line?”source ↗

“Depends on your jurisdiction. I believe mine prohibits the showering being downstream of the toilet”source ↗

“I need a new washing machine and I don't know if these pull forward to shutoff, or one back and one forward. They wiggle around because the pex isn't stiff and I'm nervous about trying to force them.”source ↗

“Not a plumber. Trying to order replacements for my old leaking fixtures.”source ↗

“Is this compression or FIP?”source ↗

“Any code related/not best practice stuff?”source ↗

“It was under my mother in laws house leaking, I replaced the section of pipe but wondering if this had some function I don’t know about? Why would someone drill a hole in the water line like that? I’m confused and kinda concerned”source ↗

“Just got my first house and one of the first things I'm sorting is installing a food waste disposal”source ↗

“Question is how to best get that AAV into the system. Space constraints mean I need to have the rough layout in the pictures.”source ↗

“Struggling to get my head around translating words into pipes but I think I understand.”source ↗

“Absolutely- I will have access to disassemble to where I wouldn't have to snake but thats just another point to why this feels like a bad idea as much as I want it to work”source ↗

“Can you help me understand how the plumbing enters my house?”source ↗

“So what’s happening under ground here?”source ↗

“I’m confused why the elbows at the back flow are pointing toward the street. I want to install an on/off valve to the main supply line before it enters my crawlspace because right now there is no shut off other than at the meter.”source ↗

“I'm kind of stuck on how that transition would work but came up with running a hose from that 3/8" outlet to a straight adapter as linked... and then transitioning to PEX.”source ↗

“Is this the best route? Or am I just not finding the right connector/adapter?”source ↗

“It’s transitioning from the existing water supply from the sink (3/8 compression) to Pex.”source ↗

“I’m not getting slow draining or anything, just looking under my sinks and saw this, thought I’d check in.”source ↗

“What the fuck kind of DIY drum trap is this? Is that just open on the top?”source ↗

“I'm going crazy because people keep giving me incorrect information on purpose.”source ↗

“I just don't know which way is up at this point. I just need to go from my stub line to my riser and then my rpz.”source ↗

“Should I separate them, and have them go out of the basement in their own discharge pipes ?”source ↗

“I need help. I've been trying to understand the angles and it seems like there's no straightforward to connect these pipes. or am i missing something?”source ↗

“I now need to fix those leaks, and think a real nitrogen setup would benefit me. I have the standard 1/4" fill valves (pictured) on the high and low side, so I just need whatever fittings and valves go from a rental nitro tank to the access ports.”source ↗