The building's PLUMBING.
The Big Bang Theory Season 4, Episode 18
You said the casita has PLUMBING?
Breaking Bad Season 4, Episode 3
...suggest that Leonard is humorously
mocking your efforts in space PLUMBING.
The Big Bang Theory Season 2, Episode 22
...but it's nice to know
everything's okay with your PLUMBING.
The Big Bang Theory Season 4, Episode 18
and not pick up a few things
about PLUMBING.
The Big Bang Theory Season 10, Episode 4