seeking a plumber referral

See this referral request from a Truxton Circle resident:

I`m looking for referral for a great plumber. We have a leaking pipe in our wall and are afraid there might be a complete mess behind the drywall, so want to get an experienced and reasonable plumber to take a look.

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? leak perhaps causing water to pool around basement door ?

From a Randolph Place NW household:

We have a slowly growing damp patch under the door sill, and the wall to one side, of our basement rear door (entry/exit for the apartment down there). The area is directly beneath our kitchen sink and dishwasher area on the first floor (so, one floor up). My hunch is we have a leak from the pipe(s) feeding/draining the sink and/or dishwasher, which is causing water to pool on the ground level (and within the wall) around that basement door. Is a plumber the right guy to call for this? An appliance person? Can they/should they get into a wall (through drywall or anything else) to take a look? If any Bloomingdalians have had something similar, I`d love to hear how they handled it.