I'll caveat this by saying I am not a dog owner.
We have had a lovely white rendered wall built in our front garden. I cannot tell you how many dog owners I have seen pause at our wall to all their dogs to cock a leg and piss down it. Which is leaving marks! It is not rocket science that if you pour yellow piss down a white wall it will stain.
AIBU for this to piss me off? I'm not blaming the dogs, but couldn't the owners tug them on! It's getting to the stage I thinking of putting up a sign or banging on the window when I see it!