“Mine seems louder at night, which is odd.”
Funny how every little noise in a house turns into a symphony after midnight. I’ve had tenants swear there was a waterfall behind the wall, only to find out it was just the pipes settling after a hot shower. That said, hissing is one of those sounds I never ignore for long—sometimes it’s just pressure, but sometimes it’s a sneaky leak trying to ruin your drywall.
I’d second the advice about checking for damp spots, especially around the shutoff valves and along the baseboards. If you’ve got access, run your hand along the pipes (carefully—nobody needs a surprise burn). If you start seeing water stains or that telltale musty smell, it’s time to dig deeper.
And yeah, pipes do seem to have a flair for drama at night. Maybe they just like an audience...