Determine when a permit is required for a French drain installation

Steps

1. Determine whether the drain discharges on-site (dry well/infiltration, no off-property discharge) or conveys water off-site (storm sewer, ditch, neighboring property) — many jurisdictions only require a permit when water is directed off-site or into the public storm system, so the discharge point is usually the trigger, not the trench itself.
2. Check the local stormwater/land-disturbance permit thresholds with the building or public works department — exemption thresholds (disturbed area, pipe size) vary significantly by jurisdiction and shouldn't be assumed to match another municipality's rule.
3. If the drain connects to the municipal storm sewer, expect a separate tap/connection permit (often issued by public works or the sewer utility, not the building department) in addition to or instead of a building permit for the trench work.
4. Check for floodplain-development or easement-encroachment permit requirements if the property is in a mapped floodplain or has a recorded drainage easement along the path.
5. Confirm whether a licensed contractor is required to pull the permit in that specific jurisdiction — some allow homeowner-permitted drainage work, others require a licensed plumbing, grading, or waterproofing contractor.