Mark, Jay J clarifies an important point ... be sure that the SEWER that you refer to is a STORM SEWER, not a sanitary sewer. Jay J is correct, you are not supposed to load the sanitary sewer with rainwater or other drainage (like swimming pool cleaning, etc.). The two types of sewer systems serve very different purposes. Again. be sure that the sewer system that you mentioned in your note is the storm sewer. If not, and if there is no storm sewer for your property, then you likely will need to divert the rainwater to the street, as Jay J says. I think it would be wise to have some advice from a local landscape architect about the drainage options for your specific parcel of land. Good luck.