water seepage by septic tank pipe

Hi! We are having problems with some seepage through our concrete block foundation around an old disconnected cast iron septic tank pipe (8"?). The wall gets damp only during spring run off and after major storms. Our downspout comes down that corner of the house but we have extended it out about 6'. However, our neighbour on that corner is a fourplex whose downspout for the entire back roof comes down and ends closeby our house. The owners are not co-operative with our suggestion to reroute his downspout away from our house. There does appear to be some draintile etc by the house. My husband has tried to caulk around the pipe from the inside of the house but that was only a very temporary fix. Now he is going to dig up the backyard by that area down about 4' or so and try to seal things from the outside of the foundation. Would anyone be able to tell us just how to most effectively seal up this problem and also what we should expect to find with this old cast iron pipe through the wall? We are totally unfamiliar with septic systems (the house is now on town water/sewer). We appreciate your help!

 

As a general rule, a property ower is legally responsible for the water discharged from his property, especially from a drain line such as a system of gutters and downspouts.