Mechanical/Electrical/Plumbing Permit

What is a Mechanical/Electrical/Plumbing Permit?

A mechanical/electrical/plumbing permit is for projects such as:

  • Water heaters
  • Air conditioners
  • Furnaces
  • Electrical service upgrades
  • Temporary electric services
  • Plumbing repairs/changes
  • Water service repairs/installations
  • Sewer lateral repairs/installations
  • Lawn irrigation
  • Fire sprinkler/alarms on commercial projects

How Do I Apply?

To apply for a mechanical/electrical/plumbing permit, please visit the Building Construction Permit section of our Citizenserve Citizen Access Portal.

What Will I Need to Submit?

  • The names/business names of contractors that will be conducting work on the project
  • Estimated cost of construction

Fees and Plan Review

The plan review process for this permit type can typically be completed on the same day. When the permit is ready, you will be notified via email that the permit is ready for pick-up as well as the final amount of the permit fee.

Building permit fees (PDF) are based on cost of construction. at the time of application, you will provide us with your estimated cost of construction and our plan reviewers will calculate an estimated cost of construction per ICC Building Safety Journal. The higher of these two estimates will be multiplied by 0.0073. This amount, or the minimum permit fee, whichever is higher, is the building permit fee that will be charged. There may be other fees associated with your permit, such as floodplain permit fees, land disturbance fees and other fees as applicable.


At least one inspection is required. When the permit is issued, the necessary inspections required will be listed on your permit card. At the inspector's discretion, some inspections may not be applicable to the particular permit in question. The inspector will note those inspections are "N/A" at a later date.

Inspections must be called in the Community Development office by 5 p.m. the business day prior to your requested inspection date. To schedule your inspection, call 636-949-7345. If it is necessary to cancel or change your inspection, please do so as soon as possible. Also, please remember to post your permit so that it is visible from the street.


If you have any questions, please contact the St. Charles County Building and Code Enforcement Division at 636-949-7345.