Whether a retaining wall needs a permit depends on where your property sits. There is no single South Hills rule, and a wall that needs nothing in one township can need engineered drawings in the next. This guide lists what each municipality's own website says, with a link to the page it came from. Where a township's site did not give us a retaining wall rule, we say so and point you to the office instead of guessing. Everything below was read from those sites in October 2026, so confirm with the township before you dig.
Mt. Lebanon. The borough's permit procedure says that a new, replacement, or relocated retaining wall over 4 feet in height requires a permit. The application takes a residential building permit form, two copies of a to-scale property survey bearing the surveyor's seal, and two copies of engineered construction drawings with a Pennsylvania registered engineer's seal and signature. The drawings must cover length, height, grading, reinforcement, backfill, and drainage. The wall must sit entirely on your property, stay off rights-of-way and easements, and sit at least 5 feet from the side and rear lot lines. A wall over 4 feet also needs a 48-inch safety fence along the top where there is a fall hazard. Source: Mt. Lebanon, Permit Procedure for Retaining Walls Over 4 Feet (dated March 2022). The inspection office number printed on it is 412-343-3408. Our Mt. Lebanon page covers the rest of what we do there.
North Huntingdon. The township's permit FAQ states: "Less than 4 feet does not require a permit. Over 4 feet requires an engineered design and permit application." "Retaining Walls Above 4 feet" also appears on its list of work that needs a permit. Source: North Huntingdon Township permit FAQ.
Whitehall. The borough's permit page says: "If your project includes a retaining wall 4' (four feet) or higher, please use the BIU application." It does not address walls under 4 feet. Source: Whitehall Borough permit applications. Borough office: 412-884-0505.
Scott Township. The township lists "Adding, modifying or replacing a retaining wall" among the projects that need a building permit and offers a retaining wall permit application for download. It states no height threshold. Source: Scott Township code enforcement. Questions go to 412-276-5300, ext. 252.
Upper St. Clair. The township's building permit page includes retaining walls in the list of work that requires a permit, with no height or size threshold stated. It also requires a permit for grading a lot, and a stormwater management plan for any project adding over 400 square feet of impervious surface. Source: Upper St. Clair building permit applications. Community Development: 412-831-9000, ext. 5010. See also our Upper St. Clair page.
Peters Township. The township's residential permits page does not mention retaining walls. It does say that Building, Zoning, Fence, and Demolition permits must come with a plot plan or survey, and that fees are set in Chapter 195 of the Township Code. That chapter, adopted in Ordinance 920, lists a flat $55 for a fence, fence-like barrier, or retaining wall under four feet in height. Sources: Peters Township residential permits and Ordinance 920, Chapter 195 Fees. For the height rules themselves, call the Planning Department at 724-942-5005. Our Peters Township page has more on working there.
For these, we could not find or open a retaining wall rule on the municipality's own website. That does not mean no permit is needed. It means the rule was not available online to us, so call the office before you plan a wall.
The number you will see most often is 4 feet, and that is where Mt. Lebanon, North Huntingdon, and Whitehall draw their lines. But Scott Township and Upper St. Clair list retaining walls as permit items with no height stated, so a short wall is not automatically exempt everywhere. Setbacks, grading, and stormwater rules can apply on their own, whatever the wall height.
Our retaining wall price calculator page notes that walls over about 4 feet usually need a permit and geogrid, and that we handle the permit and inspections. If you are planning a wall on a slope, start with our retaining wall page, then call your township office with the wall's length, height, and distance from the property line.
It depends on the municipality. North Huntingdon says walls under 4 feet do not require a permit. Scott Township and Upper St. Clair list retaining walls as permit items without a height threshold, so ask your township office before building.
The homeowner is responsible for the permit, even when a contractor does the work. Q&A Landscaping handles the permit and inspections on walls that need one.
Call the township or borough building office and ask three things: the height at which a retaining wall needs a permit, whether engineered drawings are required, and how far the wall must sit from the property line.
