I was riding home tonight and I sorta heard some noise but couldnt make it out since I was in traffic.

Got home and wheeled my bike in the hallway of my apartment complex and I heard some noise so I flipped the bike over and I think it was the disc brakes.... both front and back brakes. Sounded like they were rubbing but both of them?

Could it be road grit? It was raining and wet when I rode home. Could road grit get into the disc brakes?