Water under driver seat

I am noticing a good amount of water under driver seat and also rear seat. Please let me know what it could be.

The usual suspects are a window leak or a sun roof leak. A air conditioner leak is usually on the passenger side.

If you have a sun roof, that is most likely and is likely just a blocked drain that can usually cleaned out with some string trimmer line or maybe some careful light compressed air. (To much compressed air can cause damage that might be expensive to repair. Be careful with that string trimmer line as well.)