Large sewer line repair and replacements and installations require permits. Although national safety codes exist, your plumber must follow local and state regulations as well. Safety codes are in place to protect the homeowner as well as the public. Permits are required to ensure the work fulfills safety code regulations. The repair or replacement of sewer lines is a large plumbing job. It requires the plumbing professional or homeowner to obtain a permit before any work is completed. Most counties list their plumbing permits online for you to see. If you hire a professional plumber to complete the work for you, he can let you know which permits are needed.