 You can get it done cheaper, but you won't get it better when it comes to comfort. We're a real go-getter. When you call for plumbing and heating, the good guys are coming. The good guys are coming. A licensed plumber must carry and show his license upon request. To become a licensed master plumber, he or she must attend four years of technical school and work 2,000 hours per year under a master plumber to qualify to take the journeyman license test in the state of New Hampshire.