I don't know for sure if it was the car wash I went through that caused the dent, but I know I'm the only one who drives my car and I didn't hit anything on the road. I recall going through a drive through wash with the rolling/wash wheels that start in front of the car and when your bumper hits them, they twirl around the car. When I went through this wash, I remember hearing a slight clunk when I hit the rollers, but didn't think much of it. It wasn't until later I saw the dent.

Lesson learned though, I have been hand washing ever since, or using the brushless car washes