Building or repairing a retaining wall in Pennsylvania: permits, digging and cost

Updated November 11, 2026 · KeystoneProGuide editorial team

Does a retaining wall need a permit in Pennsylvania?

It depends on its height and what it holds up. Under the state's Uniform Construction Code regulation, no permit is required for a retaining wall that is "not over 4 feet in height measured from the lowest level of grade to the top of the wall", unless it supports a surcharge, and as long as the work does not violate another law or ordinance.

Three things follow from that wording.

• Height is measured from the lowest ground. On a sloping site, that is usually the low side of the wall, not the side you stand on in the yard.
• A surcharge removes the exemption. The regulation does not define the word, so if your wall will hold up a driveway, a parking area, a building or a steep slope above it, ask your code office before assuming it is exempt.
• Local law still applies. The exemption does not override a municipal ordinance, a zoning rule or a historic district.

Your municipality, or the certified third-party agency it uses, enforces the code. The Department of Labor and Industry says more than 90 percent of Pennsylvania's municipalities enforce it locally, and in the rest, owners hire a certified third-party agency for residential work.

What is different in Philadelphia?

Philadelphia's line is lower. The city's building permit page lists "retaining walls up to two feet in height" among the projects that often need no permit, half the state figure, and only for properties not on the historic register. A permit is also needed for excavation that cuts more than five feet below the adjacent grade.

Two more city rules matter:

• Ownership. The Streets Department says retaining walls, like sidewalks and driveways, are the owner's private property, and that every owner with deed rights to a shared alley, driveway or retaining wall must share the cost of repairing or rebuilding it, even if only part of it needs work.
• Historic properties. On a listed property, the Historical Commission reviews walls, fences and site work as well as masonry repair.

Who pays when a wall is shared?

In Philadelphia the Streets Department's rule is that all owners with deed rights share the cost. Outside the city no source read for this guide sets a general rule, so the answer is in your deed, any recorded agreement and your municipality's code. Settle it in writing with your neighbor before a contractor starts, and make sure the contract names who is paying.

Do you need to call 811?

Yes. A wall needs a trench or footing, and Pennsylvania 811 says you must contact it whenever you intend to dig, whatever the depth. Requests go in three to ten business days before the work. If a contractor is building the wall, the contractor makes the call, and you can ask for its eleven-digit serial number. Utilities may not mark customer-owned lines such as garden lighting or pool connections; private locating companies can.

What are the signs an old wall is failing?

The National Park Service (NPS) lists the conditions to inspect on masonry: cracking, spalling, bowing, sweeping, leaning and mortar deterioration. For a wall holding back soil, leaning and bulging are the ones that show it has moved. The NPS names water as the greatest threat to masonry, and lists the ground itself among its sources. Look at where water goes: Penn State Extension's advice to send downspouts away from foundations applies to any wall, and a wall wet at the base or stained with white salts is taking in water.

Repairs to an old stone or brick wall follow the same rule as a house: the NPS says pointing mortar should duplicate the old in strength and composition, and that coating old masonry with hard portland cement is never recommended.

What does a retaining wall cost?

Angi's national figures:

Angi says height and length drive the cost, with taller walls costing more per foot because they need structural reinforcement. No source read gives a Pennsylvania figure.

What should you ask a contractor?

• Will this wall need a permit here, and will you get it?
• How will it drain water from behind it?
• What will it sit on, and how deep will you dig?
• Will you call 811, and can I see the serial number?
• How will you cut block or stone, and control the dust? The Occupational Safety and Health Administration says cutting stone, brick, block and concrete releases crystalline silica.
• Are you registered as a home improvement contractor? The Attorney General's definition of home improvement covers construction and repair at a private residence on jobs over $500.

For permits generally, see what Pennsylvania requires. For wider price comparisons, see the cost guide. Contractors are on the masonry contractors page.

Sources

1. 34 Pa. Code § 403.62. Permit requirements and exemptions., Commonwealth of Pennsylvania (Pennsylvania Code)
2. Uniform Construction Code, Pennsylvania Department of Labor and Industry
3. Get a Building Permit, City of Philadelphia
4. Maintenance, City of Philadelphia, Department of Streets
5. Get approval for work to a historic property, City of Philadelphia
6. Homeowners, Pennsylvania One Call System (Pennsylvania 811)
7. FAQs Homeowners, Pennsylvania One Call System (Pennsylvania 811)
8. Common Problems with Brick Masonry, U.S. National Park Service
9. This Masonry is for the Bees!, U.S. National Park Service
10. Mortar, Unsung Hero of History, U.S. National Park Service
11. How Can I Control Stormwater on My Property?, Penn State Extension
12. How Much Does It Cost to Build a Retaining Wall? [2026 Data], Angi
13. Silica, Crystalline - Overview, U.S. Occupational Safety and Health Administration
14. Frequently Asked Questions: Home Improvement Contractor Registration, Pennsylvania Office of Attorney General