Answer: You probably should take measures outside to control the runoff near the foundation, but for the moment look at the sump: You should use the biggest sump pit you can manage. Look at HD for what they have in plastic sumps for this purpose. You want one with no openings in the sides or bottom. If the pump is small and the rate of runoff into the crawl is small, you can even get away with a very large plastic bucket. Place a few bricks on the bottom of the sump to raise the pump; that will prevent silt from entering the pump. With runoff on a dirt floor, you may have to clean it out frequently. In general, rain water is not permitted to enter the city sanitary sewers. If you have separate storm sewers, it can be pumped into a downspout connection. If your downspouts discharge onto the ground, the sump pump will have to as well. Pipe it where it won't run back into the house. You'll have to consider freezing of the discharge pipe. (It may be easier in the short run to dump it in the sewer drain...) Be sure the outlet for the pump is grounded