What matters for project planning
The stormwater program is the record that reaches this work, because below-grade waterproofing is mostly an exterior drainage project. Where water is routed once it leaves a foundation is the regulated question -- discharge toward a neighboring property or into the municipal system is not simply a design choice -- and recorded drainage and utility easements frequently run exactly where an exterior curtain drain would want to go, so they are worth pulling before a scope is priced. Historic designation reaches below-grade work only where it becomes visible at grade, such as a new areaway or an exterior stair.
Official sources
Verify the property, not just the city
City-wide guidance can't establish a specific parcel's flood zone, historic designation, stream buffer, permits, soil, or concealed construction -- confirm those with Columbia's authority and the provider.
Reviewed in 2026; requirements and maps change, so confirm what's current.