Interestingly enough I rehabbed a row house in Society Hill, Philly, awhile back, and was faced with a similar problem. The repair essentially entailed digging a trench around the perimeter of the basement and running a underground drain, which in turn fed a sump pump. There was also a need to waterproof the walls, or something like that, because the house I was working on was 230 years old, and there was something about the foundation walls that needed special attention.
Anyway, it was messy, but this particular home did not have a finished basement. The floor was concrete, so jackhammers were necessary. Now, I did not do the work. The homeowners used a company named Dr. Desert Dry, which has been in the Philly area for a long time. Iím assuming they still are. They had a great reputation. I believe the work was $2500. They were very well regarded, and guaranteed their work.
If that sounds expensive, there are other ways, including sealing the basement walls and floor with special paint, and adding special channels to the perimeter floor to collect and distribute the water without the need for digging. They all work to different degrees. Itís kind of the old get-what-you-pay-for story. Due to the special tools required, basement digging is really not a DIY affair. Also, the nature of a row home, with a residence on either side and sharing common walls, opens up other issues. You donít want to compromise a party wall. Of course, you did not say you have a row home, but Iím not familiar with much else in Center City.
As it turned out, I was done with my portion of the home before the owners did anything with the basement, so I have never worked with them in a retrofit situation. However, my current home, located outside of Doylestown, was built with the Desert Dry system back in 1954. It has no sump pump, and hat no problem at all. The only problem was due to my neglect in not cleaning out the gutters, which caused one to spill over and allow water to enter through a vent well. Even then, no water reached the floor.
I would suggest getting them in for a free estimate, especially now when it is wet and they can see whatís going on. I would also get in others for different estimates. Just because one company is good does not mean others are not equally up to the task. And the problem may be much more simple than I am projecting.