Hi, I live in South Texas and its been raining a lot. My home is a new construction stucco townhouse with cinder block firewalls that are connected left and right to other townhomes. There is a slab leak in the garage and it seems to run under the tile. It is a slab concrete home. The walls and ceiling are dry. What could be causing this?

I suspect you have "hairline cracks" in your slab. If this condition still happens during dry weather and you happen to have fresh water lines imbedded in the slab and is/are leaking that could be the culprit. In any case watch out for molds and mildew.