We just bought a house and noticed that in the basement, in the sump pump pit, there are 2 pipes which come in. I think 1 is from the drain from the steps outside by the basement entrance. I noticed, whenever we use water upstairs in the bathrooms or kitchen etc, the water from this other pipe/hole comes into the pit even though there is no rain outside or anything. Of course when this water comes, the water is drained by sump pump. I also noticed when sump pump runs, again the water comes from that hole/pipe. I thought may be the sump pump is not being thrown far off and the water is coming back in... but I went to see and the sump pump is throwing the water outside at least 20 ft away (on slope) without any chance of this water coming back in. Can anybody tell me if it is normal that when water runs through main drain line, some water comes in the sump-pump pit as well? The reason I am asking is because the main drain line in out basement is above grade. We made a new bathroom in the basement and put an ejecter system. The outlet from this ejecter we put in the main drain. So far we only turned the clean water and I noticed whenever I run this and my ejecter system throws the water in the main drain line, the water comes in the sump pump pit from that other hole/pipe I discussed above. So I am confused as to when we start using the toilet, the dirty water will come in the sump-pump pit. Is it possible?
Thanks for your help