Here is some vocabulary related to the bathroom.
Where is the bathroom?
Can you tell me where the bathroom is please?
May I use your bathroom?
I need to wash my hands.
Where is the light switch?
How do you turn on the light?
The toilet will not flush.
There is no toilet paper.
There is no hot water.
There are no towels.
The sink/shower/tub won't drain.
The bathroom is dirty.
The bathroom has not been cleaned.
There is a problem with the ....