Can't flush toilet in apartment

[xoJasberry]

The title already explains my problem.

When I walk up to the toilet in my apartment and press "E", nothing's happening. It's the only one that is still missing for the achievement :(

What am I supposed to do now?

[Laurence]

For me, when I flush the toilet in my apartment, it doesn't make any sound, but it still counted towards the achievement.

Have you tried going back through all the levels just in case the game thinks you missed one?

You don't have to finish the level, you can start it, flush the first toilet you find, then click abandon mission. It'll still count towards the achievement.

I found it hadn't registered for me on one of the earlier missions.