Retaining Walls: Gaithersburg vs Rockville
How do retaining walls rules compare between Gaithersburg, MD and Rockville, MD?
Gaithersburg and Rockville have similar restriction levels.
Gaithersburg, MD
Montgomery County
Gaithersburg permits retaining walls where changes in street grade, width, or alignment make them necessary. Section 24-167 exempts retaining walls from the corner lot sight triangle restriction when they address grade changes. Retaining walls over 4 feet typically require a building permit and engineering review.
View full Gaithersburg rules →Rockville, MD
Montgomery County
Rockville requires a building permit for retaining walls over 4 feet from footing to top. Maximum height is 6 feet 6 inches. Walls must comply with IRC Section R404.
View full Rockville rules →Key Facts Comparison
| Fact | Gaithersburg | Rockville |
|---|---|---|
| Permit Threshold | Over 4 feet requires permit | Over 4 feet from footing to top |
| Grade Changes | Retaining walls permitted | - |
| Corner Lots | Exempt from sight triangle | - |
| Engineering | May be required for tall walls | May require PE-stamped plans |
| Maximum Height | - | 6 feet 6 inches |
| Code Reference | - | IRC Section R404 |
Highlighted rows indicate differences between cities.
Gaithersburg FAQ
Do I need a permit for a retaining wall in Gaithersburg?
Retaining walls over 4 feet in height generally require a building permit and may need structural engineering review. Shorter walls may still need a permit if they affect drainage or are near property lines.
How is retaining wall height measured?
When a retaining wall also serves as a fence, height is measured from the grade on the higher side. The wall portion and fence portion may be evaluated separately for code compliance.
Rockville FAQ
When do I need a permit for a retaining wall in Rockville?
A building permit is required when the wall height exceeds 4 feet measured from the bottom of the footing to the top of the wall, or when the wall supports a surcharge such as a driveway or structure.
What is the maximum retaining wall height?
The maximum height is 6 feet 6 inches. Walls over 4 feet typically require engineered plans prepared by a licensed professional engineer.
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