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.

Hello. You're making great decisions today. well done! I arrive with the product instructions downloaded, read and ready with a tool kit custom fit for your needs. Your accurate description prepares us for success! Contact me with any details or info you like. I strive for careful, clean work and great communication with you so I understand your vision and ultimate goal. See you soon! Philip
An apprenticeship is the most common pathway to becoming a plumber. Many unions and businesses mandate that an apprentice receive a minimum of 246 hours of technical education, which could include instruction in math, applied physics and chemistry, and up to 2,000 hours of paid, practical training working with an experienced plumber. Safety training is also an important component of the process, since injuries are common in this line of work. "We have many hours worth of [Occupational Safety and Health Administration] training before we go on to a job site," says Patrick Kellett, the administrative assistant to the general president for the United Association of Journeymen and Apprentices of the Plumbing, Pipe Fitting Industry of the United States, Canada and Australia. "We're very conscious of the dangers that come with working in construction."

Rick’s Plumbing has been a mainstay within New Haven and Fairfield Counties since 1992. As a premier local plumbing service, we have been around for the community to complete any type of job – big or small. We only hire skilled professional plumbers to complete each task for our customers, ensuring the highest level of service is achieved within the shortest time possible. Whether you are looking for plumbing service or heating service, we’ve got you covered.
The Home Depot has a wide selection of high-quality plumbing parts including sump pumps, water heaters, HVAC systems, pipes and much more. The Home Depot even has eco-friendly plumbing options to help you save money and live green. If you need professional advice or installation assistance with any of your plumbing projects, turn to The Home Depot to help you finish your plumbing project. 
 CON'T FROM COMMENTS EARLIER.  However,  the  installation took less than 3/4/ hour and was a basic regulator with no other function.  Looking up the price afterwards, invoice did not list type or price, it appears that it would have cost me around $60 for the regulator and another $15 or so for the additional supplies necessary to install it and it was really a rather simple job with easy access.    Given that, it seems that $300 for less that  an hours worth of on site work,  company says it does not include commute time in its prices, is a little high.  While flat rate quotes are nice, they must take into consideration situations where the work load differs depending on the circumstances.  Therefore, unless you are at the upper end of the harder work needed than the average job. it can be argued that my estimated price of $300 for labor was more than a little high.  Maybe I am wrong since I have not used their services for years and  am not knowledgeable of the costs of equipment and professional labor today.  
Present-day water-supply systems use a network of high-pressure pumps, and pipes in buildings are now made of copper,[25] brass, plastic (particularly cross-linked polyethylene called PEX, which is estimated to be used in 60% of single-family homes[26]), or other nontoxic material. Due to its toxicity, most cities moved away from lead water-supply piping by the 1920s in the United States,[27] although lead pipes were approved by national plumbing codes into the 1980s,[28] and lead was used in plumbing solder for drinking water until it was banned in 1986.[27] Drain and vent lines are made of plastic, steel, cast-iron, or lead.[29][30]
Despite the Romans' common use of lead pipes, their aqueducts rarely poisoned people. Unlike other parts of the world where lead pipes cause poisoning, the Roman water had so much calcium in it that a layer of plaque prevented the water contacting the lead itself. What often causes confusion is the large amount of evidence of widespread lead poisoning, particularly amongst those who would have had easy access to piped water.[14] This was an unfortunate result of lead being used in cookware and as an additive to processed food and drink, for example as a preservative in wine.[15] Roman lead pipe inscriptions provided information on the owner to prevent water theft.

Rooter Plumbing Co