Interior drainage usually does not require a building permit, though discharge must comply with MSDGC or SD1 rules. Exterior excavation does require a local building permit and utility locates. Permitting and utility locates are handled as part of any job that needs them, before digging starts.
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Permit requirements depend on the scope and the jurisdiction. Interior perimeter drainage installed inside the existing basement generally does not require a building permit in most Greater Cincinnati and Northern Kentucky jurisdictions, because it is not structural work and does not alter the building footprint; however, the sump discharge must comply with the local stormwater and sanitary rules (MSDGC on the Ohio side, Sanitation District 1 on the Kentucky side), and that compliance is part of how we design the discharge. Exterior excavation is different: digging alongside the foundation typically does require a local building permit, and it always requires utility locates (the free 811 service) before any excavation so that buried gas, electric, water, and communication lines are marked and avoided. Crawl space and basement encapsulation usually does not require a permit. Egress-window installation may require a permit because it involves cutting a new or enlarged opening in the foundation wall and must meet egress code for the opening size and the well. Permitting and utility locates are handled as part of the job scope whenever the work requires them, so you are not navigating the local building department or the locate service yourself, and every job is built to the applicable code. Individual municipalities across the Cincinnati metro vary in how they treat each scope, and Northern Kentucky counties route through their own offices, so the assessment includes confirming what your specific address requires. A contractor who proposes exterior excavation without mentioning permits or locates is a red flag, because skipping locates risks striking a utility line and skipping the permit creates a problem that resale inspections and future permitted work can surface.