When Do You Need To Pull A Permit When You Do Service Plumbing? If You Go To A Service Call Where A Drain Is Leaking In The P-trap Or A Fitting In The Drain System That Doesn't Meet Today's Code For Plumbing, Can You Replace The P-trap Or S-trap And Go On Your Way Or Do You Have To Pull A Permit And Go To Extreme Measures To Properly Vent The Fixture And Have To Charge The Customer For A Few Hours Of Updating Their Plumbing?

It has been my experience that the code requires a permit to 'break the trap seal' or replace a fixture or distribution piping or drain piping. However, few do it. Check to see how strict your municipality is on this. Most do not enforce those codes.
Many municipalities do want a permit for a new sewer line, a new water service, a repipe, a new water heater, a remodel, an addition, or a new septic tank and fill line. It has also been my experience that an extremely low number comply with no problems.