Call town hall and ask for the building inspector department. The restrictions depend on the towns setbacks, conservations buffer zone restrictions and  if there is digging then National Grid would need to come by and mark the utility lines to make sure you don't hit the gas or water line. Each town has specific rules and they can change anytime, so sometimes your neighbor may have a structure to close to the property line, but they may have been grandfathered in because of the date the law was set.

Quincy Building Dept - http://www.quincyma.gov/Government/INSPECT/Building.cfm

Milton Building Dept. - http://www.townofmiltonny.org/town-services/building-department

Also to note, when ever your ready to buy a new home your buyer's agent will be happy to retrieve this information for you.

Thanks David, i looked into Milton's and most seem fairly reasonable. Well except running a brothel from your home.

I am currently working with Liane, thanks!

I was happy to help!