Oops, it doesn't look like 'world plumbing day' is a national day..

Other days

boy friend

Boy Friend Day
self appreciation

Self Appreciation Day
hannah

Hannah Day
gum

Gum Day
artists

Artists Day
ride the wind

Ride The Wind Day
pick me

Pick Me Day
fiancee

Fiancee Day
ruby

Ruby Day
nae nae

Nae Nae Day