Is it bad that this expansion tank is installed this way?

Toilet/sink vent code question

I am installing a toilet and sink under a staircase and have limited options for venting. Can I use a 1.5” vent in the configuration of the drawing to vent both the toilet and sink? I am trying to avoid running a 2” vent through a top plate and support studs. I am in the U.S. (Louisiana)

Should I caulk these areas?

I circled the areas in red! The area circled in black on the bottom has an open hole, im assuming I don't caulk that? Thank you so much!

Toilet tank constantly losing water after it fills up.

I am having an issue with my dual flush American standard toilet. After I flush the toilet it fills up fine but slowly the tank leaks out and then it starts filling up again repeating the cycle constantly. I let it fill up and watched it slowly drown but can’t see anything going into the actual bowl not from the sides at least. What is my problem here? What do I tweak or what do I replace?

Loosen 1990s Kohler handles?

My washer machine all of a sudden started leaking like CRAZY when in use.

My husband seems to behave it’s a hose or something that he can fix himself. Now don’t get me wrong the man is super handy and has general knowledge about all home repair issues, but I’m worried this is going to require professional help or just a brand new one. What you can’t see is that it’s started leaking so bad the carpet is half way soaked, just now it leaked in a completely new direction it never has before getting all the whites laid out to be laundered soaking wet. Every use it gets way worse. Please help me have a better understanding of what maybe wrong and the best course of action!! I wanna let my husband try, but not if it’s just going to lead to a worse situation. If we can avoid getting a new one that would be preferred seeing as we just had our first baby 8 months and are desperately trying to save in all places we can! Thank you for any advice and suggestions!! It’s much appreciated!

What are these?

Pretty sure these pipes run up to my kitchen faucet. These look like saddle valves but I don’t think they are?

Can I install a bidet on this ?

Are there sewer flex lines for connections where soil/foundation sinks? Driveway is sinking and pvc keeps getting disconnected.

It hasn’t rained in months in Texas and my driveway is sinking some. My sewer line from the kitchen is disconnected so water is draining straight to my driveway. Is there a flex hose or something I could use for the connection from the house to the ground line that would be able to handle the soil movement?

Curious

I was having a cocktail at a local establishment and saw there gas meter on the patio. If someone was to turn the blue valve handle would it shut gas off to the building? Just wondering why this area isn't behind a gate.

Drain on hot water heater.

I have been given the go ahead to drain our unit’s electric hot water heater, which is definitely full of rust,iron, dirt etc. I have watched lots of good tutorials… but how does this grey plastic drain valve work?