How to identify unknown plumbing parts in a building

“does anyone know what this thing is? shut off valve seems believable, if inconvenient--both in operation and proximity to the joist.”source ↗

“if I knew this thing's name, it would be a lot easier to research. just trying to swap out a very old dryer for a slightly less old dryer, but nothing can ever be simple, naturally.”source ↗

“My issue is the brand is not labelled on the fixture.”source ↗

“Does anyone have a magic catalog or seen a similar item, to be able to identify it? Or any suggestions?”source ↗

“This pipe comes up from the basement concrete floor about a foot from my water tank. I would think it's a drain so I can empty the tank but where would that even go? A flashlight reveals nothing.”source ↗

“Can anyone help me identify this component of my buildings plumbing?”source ↗

“I think it might be some kind of backflow valve but am unsure and looking to see if anyone can help identify it.”source ↗

“We just bought this home a month ago and this silver cap is on our kitchen sink. I thought it was a soap dispenser that had been broken. But when I look under the sink it has tubing with one side that connects to the dishwasher and the other to the garbage disposal. Any idea what it is?”source ↗

“Wanting to get it out and replace it with an RO filter to treat our well water. Is that doable?”source ↗

“Suffice to say, I live in a >100 year old building, and that means it comes with some... Interesting... hacked together systems, and really old plumbing joined to modern pvc.”source ↗

“We've been experiencing some drain issues recently, and i recently figured out it all goes through... whatever this is.”source ↗

“Why have I never seen one of these anywhere else I have lived?”source ↗

“Can someone please explain what the thing circled in purple is, and what purpose it serves (if any)?”source ↗

“I assumed it’s some sort of plumbing junction “box”, but the mix of hot and cold water inlets/outlets and overall routing to it/from it has me confused.”source ↗

“I’m a novice but can usually figure this stuff out, but this one has me stumped”source ↗

“Can someone tell me what kind of shower stem this is?”source ↗

“So this was done when I was off site years ago. Now I want to actually put in a washer. What exactly am I looking at? Do I need a plumber to connect the lines to the washing machine or am I just looking at protective coverings?”source ↗

“All I know is one is hot at one is cold. I don't know if these are just capped off and I need new valves put in, or if I just need to pull something off and screw in thr new lines.”source ↗

“Considering buying a 1985 house with a main water line coming in under the basement slab that looks odd.”source ↗

“Anyone know what is going on? Should I plan on replacing this sooner than later if I buy the house?”source ↗

“These two things are on the sidewalk, directly outside my condo building. Every once in a while, it overflows w liquid and sometimes it looks like soggy toilet paper too. I don’t know if it’s just in my head, but I swear i smell piss today.”source ↗

“Is this an overflow for residential plumbing? Should I call someone when it leaks like this?”source ↗

“Having trouble finding info about it online.”source ↗

“Just bought a house, exploring the plumbing.”source ↗

“Can anyone please tell me what these three seperate valves control?”source ↗

“I also don’t have the sprinkler control panel any longer so I can’t just shut it off”source ↗

“having trouble identifying the parts and replacements. My initial research suggests this is a pfister valve, but I am not certain.”source ↗

“Can anyone identify the hardware here, and let me know if I can replace this any specific trim kits?”source ↗

“First time homebuyer in need of help. Google gemjni gives too many different answers and Home Depot gives none.Need to find trim that will fit over this existing valve.”source ↗

“It's right on the curb in front of our building. Do I call the city? I honestly have no idea.”source ↗

“Could anyone possibly tell me what cartridge this is that needs replaced?”source ↗

“Hoping to just replace cartridge but can’t find who the maker is anywhere.”source ↗

“I'd be surprised if anyone knows the brand just from these pictures.”source ↗

“My local hardware stores couldn't find it.”source ↗

“This was apart of the spigot outside and no brand.”source ↗

“I’ve spent a lot of time googling and still can’t find a faucet cartridge that is similar to the one in the picture.”source ↗

“Couldn’t read any markings and the fixture was on the wall well before I moved in :/”source ↗

“The brass colored fitting shown here is the exit for the condensate line from my tankless hot water heater. It has been damaged recently causing water to leak out around the top of the pex line. What is this part called?”source ↗

“Was ready to purchase whole new assy but I question the connection.”source ↗

“Can't figure this out and neither could supply house.”source ↗

“No idea manufacturer of Urinal. No markings or identification.”source ↗

“Looking up that washer and it doesn’t look like a match. This has a a raised bevel and that Ferrell washer looks flat”source ↗

“The washer/piece is between the back of the faucet and the wall. Behind the handles. Not associated with the vacuum breaker or the faucet. Please help?!”source ↗

“Thank you! Our house was built in the 1950s and this is how it was setup when we moved in. We are on septic but this tank and our septic tank are not connected. Where is this water draining to?”source ↗