Housing:What's wrong with the drain?

Storyline: Soon after Marie moves into a new apartment, she finds out that the drain is clogged. Her friend Curtis is trying to figure out what has gone wrong.

Curtis: So, what's wrong with the drain?
Marie: It's clogged and the water won't go down.
Curtis: Let me take a look. You know why? It's clogged with hair. No wonder the water won't go down.
Marie: Well, I guess the people who lived here before didn't clean the bathtub.
Curtis: You're darn right!
Marie: But what should I do now?
Curtis: Don't worry. I've got some acid here. It'll help dissolve the hair down there.
Marie: Erh! It stinks! Peehew!
Curtis: Now you know you'll have to clean your bathtub every time after you use it.