Maryland At a Glance
- Permit threshold: 3 ft (most Maryland jurisdictions, including Montgomery and Prince George's counties)
- Engineer required: Required for walls over 4 ft; engineering review for walls over 3 ft near property lines
- Typical permit cost: $125–$500
- Average review timeline: 2–6 weeks
When a Permit Is Required in Maryland
Maryland uses the International Building Code as adopted statewide, with local amendments administered by counties. Most Maryland jurisdictions use a 3-foot retained height threshold — lower than the IRC baseline. Montgomery County and Prince George's County are the two largest jurisdictions in the state and both use the 3-ft threshold. Anne Arundel County (Annapolis area), Howard County, and Baltimore City/Baltimore County each have their own permit requirements. Maryland's proximity to the Chesapeake Bay watershed also means stormwater management requirements frequently apply to retaining wall projects.
Key City and County Rules
Montgomery County: 3-ft threshold, permits issued through the Department of Permitting Services (DPS). Engineering required for walls over 4 ft and for walls near property lines. Prince George's County: 3-ft threshold. Howard County: 4 ft (check locally). Baltimore City: 4 ft, permits through the Building, Housing, and Construction (BBMR) office. Anne Arundel County: 4 ft. Frederick County: 4 ft. Harford County: 4 ft.
Engineering Requirements
In Maryland, engineer-stamped plans are required for: walls over 4 feet of retained height, any wall supporting a surcharge load (driveway, slope, or structure above), and tiered wall systems where the combined retained height exceeds 4 feet. Some jurisdictions within Maryland require engineering for walls over 3 feet. When in doubt, contact your local building department.
How to Apply for a Retaining Wall Permit in Maryland
Permit applications in Maryland are submitted to your local city or county building department. Maryland does not have a statewide residential building permit office — permits are issued at the local level. Most jurisdictions now accept applications online or in person. You will need:
- A completed permit application form (available from your building department)
- A site plan showing the wall location, distance to property lines, and dimensions
- Wall design drawings (cross-section, footing details, drainage plan)
- Engineer-stamped plans if required for your wall height and conditions
- Permit fee payment
Maryland's stormwater management regulations (particularly in the Chesapeake Bay watershed, which covers most of the state) require that retaining wall projects address drainage carefully. Any wall project that changes impervious surface or significantly alters drainage patterns may trigger a stormwater management review in addition to the standard permit process.
| Condition | Permit Required? |
|---|---|
| Wall under 3 ft retained height, no surcharge | Generally Not Required |
| Wall 3–4 ft, no surcharge (verify local threshold) | Verify Locally |
| Wall 4 ft or more, standard conditions | Permit Required |
| Any wall with surcharge load | Permit + Engineering |
| Tiered wall system (combined height > 4 ft) | Permit Required |
| Wall within 5 ft of property line | Permit Required |
Frequently Asked Questions — Maryland
Retaining wall permits in Maryland are issued by your local city or county building department. There is no statewide permit office. Search "[your city or county] building permits" to find the correct agency, or use our building department finder.
Most jurisdictions in Maryland allow homeowners to pull owner-builder permits for work on their primary residence. You are responsible for meeting all code requirements and passing inspections. Check with your specific building department, as rules vary by city and county.
Review timelines vary by jurisdiction, but most residential retaining wall permits in Maryland are reviewed within 2–6 weeks of a complete application submission. High-volume urban building departments (major city cores) may run 4–8 weeks. Some jurisdictions offer expedited review for an additional fee.