When it rains and the sump pump goes on, it works like clockwork for the first 15 or 20 minutes. After that, the crock begins to rise with water and the pump runs continuously, but the water level doesn’t change. Even 4 hours after the rain, the pump is still running and the crock is still full of water. The pump is new last month and works great in light rain or for the first 20 minutes of a heavy rain. Could the problem be a clogged storm sewer line ?
Could be something in discharge pipe, take pipe loose and hook some pipe to it and run out door are window and see if it pumps out all the water, if so then the sewer is maybe stopped up . Let me know.
Bob, believe it or not I just discovered the exact problem at my own house today while dealing with the remnants of hurricaine katrina. It sounds as if you most likely have a clogged storm sewer/underground downspout line. Since around here they use very thin walled pvc for this purpose, my weekend will be spent replacing the entire run as I’m convinced that it is crushed.