Is it possible to pop off this end cap?

So, I am looking to replace an anti-siphon sillcock. My wife and I recently moved in to our house and one of the outdoor houses leaks from the inside when we turn it on. From the outside of the house, I measured where the sillcock is relative to the bathroom window. Right where the sillcock should be from the inside of the house, there is this box that is connected to a sewer vent. Is it possible to pop off the threaded end cap there? If so, I think I could just pop out that plastic box. I think that if I can remove this box that I can see how the sillcock is connected to the inside pipes and determine if it is a job I can do myself. Thoughts? Thanks in advance. I am relatively new to these types of home repairs.

Paranoid about shower leak

I’m very much an amateur and tried to replace the showerhead that came with my rental - it was screwed on way too tight so I used a monkey wrench and a lock wrench. The showerhead arm rotated about 60 degrees clockwise from neutral but is now straightened back to normal. Pic is for reference but I really don’t want to cause any leakage behind the tile (I can’t see into it since the hole is just big enough for the shower arm to come through). Should I be concerned? And how will I know if there’s a leak? TIA

Down spouts at Pikes Place, Seattle, WA

Re-using gas compression valve

Is it ok to reuse a gas compression style valve? The valve is 20 years old but still in great condition.

How do I remove this drain cap?

I want to remove this existing drain cap and is install a hair trap. I can’t for the life of me figure out how to remove this. Any advise?

What are these rubber things on top of the tank bolts?

I’m replacing my toilets hardware and it has these weird rubber things I can’t get off where the bolts are. What are these? How do I get them off?

I have two of these that are both failing for different reasons. Would like to replace the trim without soldering in a new valve. Do they make new, better looking trim kits for this?

Installed correctly?

Located in upstairs bathroom. The sink is draining very slowly. House is only two years old and we have found many issues with pipes installed incorrectly so I wanted to check before I start taking it apart.

Replacement head for Moen Chateau kitchen faucet

We took off the aerator and head of our faucet to install a Brita filter. We’ve now installed two whole house filters, but lost the aerator and head to the faucet. I bought a replacement aerator, but can’t find the adapter I beed.

Sus

Simple fix?

Was busting my nephews balls about not grooming his facial hair so he asked if he could shave at my place. He decided to add all the hair into a paper towel, ball-up the towel and then flushes it down the toilet.... I can't belive this kid lol. Anyway toilet will flush but it almost over flows. Will plunging it make it better, or should I buy a drain cleaner off some kind. I live in an apartment complex so if it's really bad I can just have maintenance take a look. Any advice?