Looking for a plumber in Chicago

[Joe Mende]

Was doing our final walk-through of a duplex in Irving Park yesterday and there's a really strong, foul smell in the basement that wasn't as noticeable before.  The basement is emptied out and there's a bathroom that hasn't been used in what seems to be about a decade.  Not sure what the smell is exactly but have to assume it's some type of plumbing or maybe mold issue?  Anyone who has some good plumber referrals would be much appreciated!