Who would we call about living next to a hoarder?

My girlfriend and I have been in a rental property for about 8 months now and our next door neighbor is a hoarder (I’ve been in her house, this isn’t normal old lady clutter, it’s full blown newspapers and who knows what else). She’s a lovely old lady and we have a good relationship with her, we’re just worried about her safety. There have been many nights where she’s fallen and called us, which my girlfriend or I go and help her up and make sure she’s ok, but we’re worried one day she may fall or have something fall on her. I just feel like it’s time we do something about it.