It is so nice to see someone talking about it. I have an off the grid system too and oh my!
I have a 1500 SF house with a full basement with a garage door (single). They’re often called “boat doors” but I keep my lawn mowers, etc. there.
The basement is unfinished and it has two red bulb chrome fire sprinkler heads in that area (155 degrees F). Direct copper pipe to the main line just after the main shutoff valve (tapped before the pressure reducer).
I guess I’m lucky. No weeping, seeping or leaking. There is a final end of line tap off from them that goes to the outside hose bibb outside the boat door.. so I can always know how good the water pressure is and measure it there at the bibb if I need to. The pressure is street pressure and that outside bibb always has a 100’ roll of hose on it (I call it my fire hose). House is 15 years old and no problems yet, thankfully.