Boston's older water mains and shared stacks in multi-family buildings mean low pressure on upper floors and galvanized risers in pre-war units. In the South End and Back Bay, shut-off valves are often buried behind built-in cabinetry — photo the access path before booking.
Winter freeze-thaw opens pinholes in horizontal galvanized runs in basement ceilings across Jamaica Plain and Dorchester triple-deckers. Opa Pro routes licensed Massachusetts plumbers who carry the right fittings for mixed copper-and-galv systems common in 021xx ZIP codes.
Gas water heaters, boiler tie-ins, and any work on main lines require licensed trades and may need Boston ISD permits. For drains, fixture swaps, and leak isolation, upload photos of the active leak, meter location, and floor level for a local price range before you share contact info.