I am having a house built. The foundation was poured in March of 2018. I noticed that the basement walls and floor are wet in two areas for the past three weeks. The area did receive a good amount of rain over this period. The house has an exterior drainage system that drains by gravity to the back of the property into a drainage pipe that leads to the detention basin. The exterior basement walls had tar applied to them as well as a membrane to keep water out. There is also a sump pump in the basement that has not been turned on during the last three weeks. The builder turned the sump pump on and it shut off in 15 seconds because there was no water in the sump hole. The builder claims that once the gutter system and final grading is done (grading looked ok to me), the walls and floor will not get wet anymore and basement will be dry in all areas. The builder also stated that since the sump pump did not have to pump any water, this is proof the exterior drainage system is working. Once I close, the limited warranty for the basement only kicks in if there is water on the floor. I am not covered for wet (damp) walls or floor.

My opinion is that the basement should be dry now because of all the basement waterproofing that was done regardless of the amount of rain. I think there is a problem with the exterior drainage system or cracks in the walls or floor that is letting moisture seep in. I also have noticed a hairline crack on the floor in another area of the basement. The gutter system and final grading will help the situation, but if there are periods of heavy rain in the future, I think this water problem will come back. The wet walls and floor now show a weakness in the water management system for the house.

What should be my course of action? Am I paranoid? Should I take the builder's word?