County permitting offices exist to both record improvements for tax purposes as well as oversee work being done to ensure that it is safe and meets code building code standards. If a job is considered new service, an improvement to existing service or an upgrade it may require a permit. In general repairs to existing systems do not require permits.
The permitting process is fairly simple, a permit is applied for, a fee is collected and then an inspector visits at various stages to ensure that work is completed correctly.
The permit process can add additional time to completion as in most cases an county inspector will need to visit and approve work being done at different stages of completion. Depending on the type of work being done this can be one or multiple visits. If the inspector has a question or finds a problem they must re-inspect the work before the job can proceed. Most inspectors require at least 24 hours to schedule another visit so this can add additional days to a job.