Your best bet is a local contractor who specializes in septic systems or drainage. A general contractor can do this work for you, but they will just subcontract it to someone who has the equipment and knowledge.
from a small leak to an all out flood, if the basement has seen any type of groundwater leak then it needs a quality basement water diversion system like watergaurd, dry trak or other options available from basement system. if water seepage is a once-a-year occurence, it needs to be fixed before the basement is finished
3 You can call a plumbing contractor to check the drain system for leaks, they should be able to at least find the leak for you. If they can't fix it, they should ba able to recommend someone who can. You can also try a Sprinkler System contractor. Again, if they can't fix it, they will direct you to who can.