I believe sewerage is included in the rates/water rates. If your property is seperately metered for water, you can pass on excess water costs. Ours isn't so we have to wear that ourselves. I don't think you can pass on sewerage but I really don't know for sure. We are in qld so it could be different where you are.

When we first rented our unit it cost us about $5k a year with a mortgage about half yours (it's a tiny one bedder). So it sounds about right to me based solely on that. Every property is different though. We looked at one unit that had body corporate fees over $5K more than ours for the privilege of having a gym, lift and pool in the building. That would significantly affect your hip pocket.