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

Other days

comfy

Comfy Day
eat what you want

Eat What You Want Day
kale

Kale Day
my little pony

My Little Pony Day
ponytail

Ponytail Day
first love

First Love Day
gum

Gum Day
prosecco

Prosecco Day
fiancee

Fiancee Day
hannah

Hannah Day