Most plumbers wont mess with the septic tank. We deal mostly with components inside the house. Did you have a vent pipe in the yard (often looks like a candy cane made of PVC) before the repair but not after? If all he did was replace the line it shouldn't cause a smell inside the house. All plumbing fixtures inside the house should have properly functioning traps. Those traps would create and maintain a water seal against the sewer gases. You should have at least one vent through the roof to equalize pressures within the drainage system. This prevents positive pressures within the system (caused by fixtures discharging into the lines, ie toilet flush) from pushing gas out through the traps, and negative pressures (the waste in line will pull air behind it like your finger over the end of a straw) from sucking water out of the traps.
Galvanized steel potable water supply and distribution pipes are commonly found with nominal pipe sizes from 3⁄8 inch (9.5 mm) to 2 inches (51 mm). It is rarely used today for new construction residential plumbing. Steel pipe has National Pipe Thread (NPT) standard tapered male threads, which connect with female tapered threads on elbows, tees, couplers, valves, and other fittings. Galvanized steel (often known simply as "galv" or "iron" in the plumbing trade) is relatively expensive, and difficult to work with due to weight and requirement of a pipe threader. It remains in common use for repair of existing "galv" systems and to satisfy building code non-combustibility requirements typically found in hotels, apartment buildings and other commercial applications. It is also extremely durable and resistant to mechanical abuse. Black lacquered steel pipe is the most widely used pipe material for fire sprinklers and natural gas.
Jump up ^ "II. The Plumbers". The Atlantic. Retrieved 17 September 2013. In the early evening of June 17, 1971, Henry Kissinger held forth in the Oval Office, telling his President, and John Ehrlichman and Bob Haldeman, all about Daniel Ellsberg. Kissinger's comments were recorded, of course, on the hidden White House taping system, and four years later, a portion of that tape was listened to by the Watergate Special Prosecution Force, which was then investigating the internal White House police unit known as the Plumbers.