joebedford wrote:
A water tank vent doesn't leak into the basement. My tanks vent is right beside the fill.
It could if the leak was near the top of the tank and it was over filled. In either case, a leak in the tank itself would not impact the pump. Unless the leak was at the pump. And the OP has tested the winterzation port so presumably would know if there was a leak in the very proximity of the pump.
They may need to drain the tank and do a similar test but draw from a bucket from the normal pump port. Just because it is drawing from the winterization port does not mean the primary works.