My roommate brought her Brita filter pitcher to the apartment with her back when we first moved in, and she stated from the beginning that I was welcome to use it. She doesn’t like drinking unfiltered water. I’ve used the Brita occasionally, but I don’t mind the regular unfiltered water from the fountain, plus it’s more convenient for me, so I’ve mostly stuck to using that. It’s been over 2 months since I’ve last used the Brita filter. However, I’ve noticed that my roommate has stopped refilling it after using it up, and leaving it on the counter empty. I haven’t said or done anything about it because I’ve been busy with work and use the unfiltered water anyways. Yesterday when my roommate got home, she asked me if I had filled up the filter, and I replied no. She got frustrated and said that it’s a shared resource and we all need to do our part. I was a bit confused because I’ve stopped using it altogether long time ago, so it’s no longer shared, and therefore it should no longer be my responsibility to fill it. I also want to point out that when I DID used to use it, I’d always refill it after emptying it out of courtesy for my roommates. I also pointed out to her that she was the last person to use it, and never bothered to fill it up since then, so it was on her to be the one to fill it up. She argued that I should just take the initiative and fill it up when I have time to do it, and she had been too busy to fill it. I argued that I was busy as well. To add context, we have a 3rd roommate who does rely on the Brita pitcher, but almost never fills it up and waits until my other roommate does it for her. In my opinion, the responsibility to fill it falls on both of them, as they are the ones who actually do use it. But am I just being petty? We had a bit of an argument about it and left things on an awkward note, but I’m not sure who’s in the wrong or not. Am I responsible for filling it up even if I don’t use it, or should my roommates be the one to do it? So AITA?