Rushing Water in South Station?

Anybody heard this?
It seems to be coming from the southbound side, just before the platform starts.
It sounds like someone's flushed the toilet and the water is rushing into the tunnel.
You can't see anything though, and you can see pretty far towards DTX in that tunnel.

I remember hearing that a week or two ago when I was standing at the north end of the northbound platform. It sounded like it was coming from along the tunnel wall further north in the tunnel towards DTX. A flushing toilet is exactly what it sounded like! It wasn't smelling too nice down there that day...I hope that's not what it was! Hopefully, its just a drainage pump of some kind discharging.

I've seen water at State drain onto the tracks a few time. It seems pretty routine. I'm not sure what the reason is though..