By "weeping tiles" do you mean the "footing tiles" that take the water that runs down the outside of the foundation wall and redirects it? If so, and they are connected somehow to the city sewer without need of a pump, that's a nice, foolproof system. I presume your footings are higher than the city sewer for that system to operate. The hole in the bottom of the sump crock may, then, connect to the pea gravel under the floor. The water table rising after heavy rains would, then, flow into the sump crock and get pumped out.