Allegheny County, PA Fence Regulations: Retaining Walls (2026)
Key Facts
- County Permit
- None: municipal UCC authority
- State Code
- PA UCC Act 45 of 1999 (35 P.S. 7210.101)
- Permit Exemption Threshold
- 4 feet (measured low grade to top)
- Exemption Citation
- 34 Pa. Code 403.62(a)(13)
- Surcharge Rule
- Permit required even under 4 ft if wall supports load
- Engineer Stamp
- Typically required for walls >4 ft
- ACCD E&S Plan Trigger
- 5,000 sq ft of earth disturbance
- NPDES Permit Trigger
- 1 acre of earth disturbance
- Erosion Control Authority
- Allegheny County Conservation District (412-241-7645)
- Max UCC Fine
- $1,000/day (35 P.S. 7210.903)
Summary
Allegheny County does not issue retaining wall permits: building authority rests with each of the 130 municipalities under the Pennsylvania Uniform Construction Code (Act 45 of 1999, 35 P.S. 7210.101). UCC at 34 Pa. Code Section 403.62 exempts retaining walls 4 feet or less in height (measured from the lowest grade to the top of the wall) unless the wall supports a surcharge or impounds Class I, II, or III-A liquids. Walls over 4 feet, walls supporting a driveway, building, or steep slope, and any earth disturbance over 5,000 sq ft also trigger Allegheny County Conservation District (ACCD) review under 25 Pa. Code Chapter 102.
§ 403.62. Permit requirements and exemptions. (a) An owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish or change the occupancy of a residential building or erect, install, enlarge, alter, repair, remove, convert or replace an electrical, gas, mechanical or plumbing system regulated by the Uniform Construction Code shall first apply to the building code official and obtain the required permit under § 403.62a (relating to permit application). (b) An emergency repair or replacement of equipment may be made without first applying for a permit if a permit application is submitted to the building code official within 3 business days of the repair or replacement. (c) A permit is not required for the exceptions listed in § 403.1(b) (relating to scope) and the following, if the work does not violate a law or ordinance: (1) Fences that are no more than 6 feet high. (2) Retaining walls that are not over 4 feet in height measured from the lowest level of grade to the top of the wall unless the wall supports a surcharge. (3) Water tanks supported directly upon grade if the capacity does not exceed 5,000 gallons and the ratio of height to diameter or width does not exceed 2 to 1. (4) Sidewalks and driveways that are 30 inches or less above adjacent grade and not placed over a basement or story below it. (5) Prefabricated swimming pools that are less than 24 inches deep. (6) Swings and other playground equipment accessory to a one- or two-family dwelling. [...] (8) Installation of an uncovered deck where the floor of the deck is no more than 30 inches above grade.
Official source re-checked September 8, 2026: the cited page had not changed since it was quoted.
Full Breakdown
Allegheny County itself does not issue building permits for retaining walls. S. 101) and its enabling regulations at 34 Pa. Code Chapter 403 apply countywide and adopt the International Residential Code and International Building Code. 62(a)(13) exempts 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 the wall is supporting a surcharge or impounding Class I, II, or III-A liquids. A surcharge means any extra load behind the wall, a driveway, patio, building, fence, swimming pool, or steep slope above the wall, and a wall under 4 feet with a surcharge usually still requires a permit.
The City of Pittsburgh codifies the same threshold in its PLI Work Not Requiring a Permit list and in Title 10 Building Code; walls over 4 feet, walls with surcharges, and any wall holding back fill from a structure typically require a residential building permit, plans stamped by a Pennsylvania-licensed professional engineer, and inspection. Each suburban municipality (Mt. ) administers UCC permits through its own building department or a third-party agency. Separately, Allegheny County Conservation District (ACCD) administers Pennsylvania's Erosion and Sediment Pollution Control Program under 25 Pa.
Code Chapter 102 by delegation from PA DEP. A written E&S Plan is required for any earth disturbance of 5,000 square feet or more, and an NPDES Construction Stormwater Permit is required at 1 acre or more. ACCD review can be triggered by retaining walls cut into hillsides, a common condition in the Mon Valley and the Pittsburgh hills. Slope protection provisions in some municipal SALDOs allow an engineered retaining wall to satisfy slope stability requirements where slopes exceed 25 percent. Contact ACCD at 412-241-7645.
Violations & Fines
Building a retaining wall over 4 feet, or under 4 feet with a surcharge, without a municipal UCC permit is a summary offense under 35 P.S. 7210.903 carrying fines up to $1,000 per violation per day plus court costs and stop-work orders. Earth disturbance of 5,000 sq ft or more without an approved E&S Plan can trigger ACCD enforcement and PA DEP penalties under 25 Pa. Code Chapter 102, including civil penalties up to $10,000 per day under the PA Clean Streams Law (35 P.S. 691.605). Pittsburgh PLI may red-tag noncompliant walls.
Frequently Asked Questions
Do I need a permit for a retaining wall in Allegheny County?
What counts as a surcharge that makes a small wall require a permit?
When does the Allegheny County Conservation District get involved?
Sources & Official References
- [1]34 Pa. Code Section 403.62 Permit Requirements and Exemptions
- [2]34 Pa. Code Section 403.42 Permit Requirements and Exemptions
- [3]Pittsburgh PLI - Work Not Requiring a Permit
- [4]Allegheny County Conservation District - Chapter 102 Resources
- [5]Allegheny County Conservation District - Submit Plans
- [6]25 Pa. Code Chapter 102 (Erosion and Sediment Control)
Other rules in Allegheny County
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