MUNICIPAL REQUIREMENTS
Use the municipality where your property sits. A Pittsburgh mailing address does not necessarily mean City of Pittsburgh rules apply.
The answer depends on your municipality and project scope. Mt. Lebanon’s guidance uses a two-foot building-permit threshold; Upper St. Clair requires zoning approval even below 30 inches. Building, grading and zoning approvals are different checks. Use your town’s official source below.
MT. LEBANON
Above two feet: building permit. Above four feet: engineering drawings.
The municipal guide calls for two property-survey copies marked with the wall location. At boundary heights or with unusual site conditions, ask the Inspection Office.
Read the official guidanceBETHEL PARK
Check the grading and retaining-wall application route.
The linked checklist requires engineer-sealed plans with grading applications and defines walls above four feet using exposed-face height. It does not establish a blanket exemption for smaller projects.
Read the official guidanceUPPER ST. CLAIR
Below 30 inches still requires zoning approval.
The small-project application adds a building permit and construction plans above 30 inches. Exactly 30 inches is not resolved by its wording; some large projects may need grading approval.
Read the official guidanceCASTLE SHANNON
Start with Planning & Codes.
The borough requires project plans and provides building/zoning and grading application routes. A wall-height exemption was not established from the reviewed guidance.
Read the official guidanceWHITEHALL
Driveway work with a wall four feet or higher uses the BIU application.
This statement is in driveway-expansion guidance. Ask the borough which application applies to a standalone retaining wall or related grading.
Read the official guidanceBALDWIN BOROUGH
Start your inquiry with the code-enforcement desk.
Applications need plans and contractor information. A complete retaining-wall exemption rule was not established. Baldwin Borough and Baldwin Township are different jurisdictions.
Read the official guidanceBRENTWOOD
Wall construction and repair are listed as permit work.
The borough page states an exemption below four feet, while separately listing excavation and grading as permit work. Confirm how the complete project is treated.
Read the official guidance