Sump pump

[baconoclock]

Was helping my parents install a sump pump a few weeks ago. I grabbed my cement saw and cut a 2x2 hole. Dug out whatever dirt was there then hit bedrock. Grabbed a jackhammer and went to work on the bedrock but it just turned to dust (limestone). Will it hurt anything to only have the pump about 1.5 feet below basement ground instead of the 2+ i was going to do?

[Duke{CLR}]

My sump pump is only 18" below the surface and it works fine. I don't think the water would come through the rock but I am not familiar with limestone. Around my home we have granite so all we need to worry about is radon.