Student Flat Water Bill

I've been living in a student flat for about a year now and I'm moving out soon. At the start of the year my flatmate said we probably didn't need to worry about the water bill because he thought it was included in our rent for whatever reason. Regardless, I don't think it was. I checked the water meter, and it reads 1040. There's only two of us living here, so there's absolutely no way we've used that much water in one year.

I'm just looking for general advice on how to deal with this. I don't have anything set up with a utilities company and now someone else is going to move into this flat soon and they've already asked me about who I pay for water. I don't really know what to do, I know I should have done something about this earlier. It just seems like the meter reading is way over.