Thanks everyone, we're back to normal now, it's fixed. Now Hanna wants to go back in the laundry chute! I don't understand, I know it was an adventure but I would think the experience of being down there with all the people and noise so close would make her want to be far away!

It was our pipe, we live on a hill and instead of a sloped pipe, there are some angles down to street level. Some stuff got caught in there (I don't even want to know what ), so it wasn't tree roots. They had some pretty powerful unclogging equipment and it turns out they were just banging away at the pipe where the angle was. But now it's fixed and we're all happy, thanks!