In the market I was cold-calling (1M+ properties north of Boston) I spent 4 hours per day cold calling - I usually got through about 200 calls (yes, it was painful).

Can anyone suggest a reliable and no too expensive plumber in the Boston Area?

Consolidated Contracting out of Boston does a good job! 

Im a Plumber in the Boston area and make good money, plus I have a side thing after my 40 hours.

I think there's still room in the Greater Boston market to achieve this goal. 

I have a leaking toilet drain and I'm looking for a good, reliable plumber in the greater Boston, MA area.

Looking for a plumber ASAP. I have a rental property that we suspect has a broken drain pipe. The unit below ours is experiencing leaking from the ceiling. I'm looking for someone who can open up the ceiling to check ...

Try FB Group such as Real Estate Unleashed for better Boston recs - there's a lot of local developers on there. 

My own view: the answer is in the linkedin/zip recruiter/monster.com Find city/metro that has largest number of engineer job opening per square miles.So you'll find:San Jose,CA ; Burlingame,Ca ; San Francisco,CA ; San Diego,CA ; Austin,TX ; Raleigh,NC ; Boston,MA, Seattle,WA and maybe even Huntsville,AL.Go follow the trail of money........and split the bet accordingly to those cities.

But with the internet and our ability to connect with randos and build webs of connections it makes it possible to invest where the numbers make sense.San Francisco, Hawaii, Los Angeles, Seattle, Boston are examples of primary markets which are NOT ideal for cashflow investing.