OK, I just moved into a house which is 12 years old. At one corner of the house in the basement, there is a sump pump pit that is about 3 1/2 feet deep and 2 feet wide with two drainage pipes leading into it. There has never been a sump pump used before with this pit. We just had a lot of rain and now this pit is filling up every few hours. I have neve let it get to the top so not sure if it is going to overflow.
ANother thing that the house was designed with, is that in the other corner of the house there is a small pit that has PVC pipe leading to the sewer tank. At times, some water builds up there and i have to open the cap and allow water to drain to the sewer.
Is it possible that when my sump pit fills, that the excess water drains to this other pit leading to hte sewer?

Any help would be appreciated.

 

It's possible, but not likely. It seems like you would be able to see an overflow line out of that sump, if that were so.
Maybe the sump has an underground line draining to the septic system, but I don't think that anyone would drain all rain water to a septic tank. It might overload the system during extreme rain.
It is more likely that normal rainfall is handled with ground absorption through gravel at the bottom of that sump, or a drain elsewhere.
I think that I would just keep an eye on it during rains, and if it appears that it is going to overflow, I would just get a sump pump to pump it out into natural drainage away from your house (street or ditch).
I definitely would not put it all into my septic system.
In most places, storm water cannot be drained to a public sewer system. It would only add to volume that has to be "treated". That's why the town sewer and storm drain systems are separate.
Good luck!
Mike