Pool of liquid on passenger side

Yesterday there was a pool of liquid on the passenger side floorboard of my fit and I park inside the garage so it's not from rain. Unfortunately my husband poured it out of the floor guard because we were in a hurry and we assumed at first it was a spilled drink. But I've thought hard and there was no drink or water bottle in the car that could've caused it.

So now I'm worried it was antifreeze or something. Has this happened to anyone with their fit before?