RETAINING WALL GUIDE • BISMARCK, ND
Retaining Walls in Bismarck: Permits and Drainage
Under the 2021 International Residential Code, which North Dakota’s state building code adopts, a retaining wall up to 4 feet tall usually doesn’t need a permit, as long as it isn’t holding up extra weight like a driveway or a slope. Height counts from the bottom of the footing, not the top of the grass. Walls taller than that, or walls with a load above them, need a permit and usually an engineered design.
Cities can change the model code, so call the City of Bismarck Building Inspection Division at 701-355-1465 before you build. And whatever the height, drainage is what keeps a wall standing through a North Dakota spring.
PERMIT BASICS
The Permit Rule in Plain Words
Section R105.2 of the 2021 International Residential Code lists work that doesn’t need a permit. It includes retaining walls “that are not over 4 feet in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge”.
So two things decide it: the height, and what’s sitting above the wall.
How Wall Height Is Measured
This is where people get caught. The 4 feet starts at the bottom of the footing, which for a block wall is the bottom of the gravel leveling pad. The wall industry’s group, the National Concrete Masonry Association (NCMA), calls for a pad at least 6 inches thick and a first row of block buried at least 6 inches.
| What you see above the grass | Buried block | Leveling pad | Height that counts |
|---|---|---|---|
| 2 ft 6 in | 6 in | 6 in | 3 ft 6 in |
| 3 ft | 6 in | 6 in | 4 ft |
| 3 ft 6 in | 6 in | 6 in | 4 ft 6 in, over the limit |
That’s our math using NCMA’s minimums. A wall that looks like 3½ feet from the lawn can already be past 4 feet by code.
What Counts as a Surcharge
A surcharge is extra weight pushing on the soil behind the wall. Even a short wall can need a permit if it holds one up. Common ones in Bismarck yards:
- A driveway or parking spot above the wall
- A shed, garage or house near the top
- A slope running up and away from the wall
- Another wall stepped up behind it
- Snow. NCMA’s best practices guide lists “plows pushing snow into the face of the wall” and “snow piled on top of the wall” as loads a design should account for. If you pile driveway snow on top of a wall all winter, that matters.
DESIGN & SAFETY
When a Wall Needs an Engineer
Section R404.4 of the 2021 IRC says walls that “retain in excess of 48 inches (1219 mm) of unbalanced fill,” or walls over 24 inches tall that hold back more than just soil, must be designed using “accepted engineering practice.” The design has to protect against overturning, sliding, too much pressure on the soil below and water uplift, with a safety factor of 1.5 against sliding and overturning.
In plain words: once a wall holds back more than 4 feet of dirt, or holds back a load on top of a 2-foot wall, someone has to run the numbers. On taller or loaded walls, NCMA also calls for geogrid reinforcement at least 60% of the wall height long and never under 4 feet. See retaining walls in Bismarck for how we build them.
BEFORE YOU BUILD
Other Rules That Can Apply
City changes to the code
The IRC is a model code. Call Bismarck Building Inspection at 701-355-1465 to confirm what applies to your wall. In Mandan or Lincoln, check with that city.
Property lines and easements
Check your lot survey or plat before building near a line. Easements can limit what you build in them, so check before building there.
Your neighbor’s yard
Don’t build a wall or drain that pushes water onto the lot next door.
811
NDSU Extension’s August 2026 release says to call 811 or file online “at least two full business days before beginning a project.” It also says private lines, like sprinkler systems and electric lines past the meter, aren’t marked by the locate service.
Contractor license
North Dakota requires a contractor license for jobs over $4,000. You can look up a contractor through the Secretary of State.
HOA rules,
in neighborhoods that have them.
BUILT FOR CLAY & FREEZE-THAW
Drainage: What Keeps a Wall Standing
Bismarck clay holds water, and wet clay that freezes pushes hard on anything in its way. NCMA’s guides spell out the basics:
| Part | What NCMA calls for |
|---|---|
| Drainage gravel | At least 12 inches of clean gravel behind the block |
| Drain pipe | At least 3 inches across, at the bottom of the gravel |
| Outlets | Every 20 to 50 feet, so water actually leaves |
| Soil cap | About 8 inches of low-permeability soil over the gravel, so rain doesn’t pour in from the top |
| Swale above | So “water is not allowed to flow over the top of the wall” |
| Backfill in cold climates | Soils with low to moderate frost heave potential |
| Site grading | “Drain surface water away from the top and bottom of the wall” |
For more on how clay handles water, see fixing drainage on clay soil.
Where the Water Should Go
NCMA says, “All drain pipes must exit to daylight or be connected to an underground drainage system,” and outlets should be “protected from crushing or plugging.” In a Bismarck yard, that means:
- Daylight the pipe at a lower spot in the yard where water can spread out.
- Keep it off the sidewalk and driveway. The City of Bismarck asks homeowners to send yard water into lawns or planted areas, not onto hard surfaces. Water on a walk in March is ice by evening.
- Keep it on your own lot, not aimed at a neighbor’s house.
- Keep the outlet clear. Check it in spring for snow, ice, leaves and grass clippings.
For bigger drainage problems around a wall, see yard drainage and grading in Bismarck.
HIRING CHECKLIST
Questions to Ask Before You Hire
- How tall will the wall be from the bottom of the footing?
- Does it hold up a driveway, a slope, a building or snow piles?
- Does it need a permit or an engineer, and who handles that?
- How thick is the leveling pad, and how deep is the first row buried?
- How much drainage gravel goes behind it, and where does the pipe come out?
- Is geogrid included, and how long is it?
- Are you licensed with the North Dakota Secretary of State?
Questions
Retaining Wall FAQ
Answers about permits, wall heights, engineering and drainage in Bismarck.
Have a wall question?
Call and tell us about the height, site and drainage concerns.
Do I need a permit for a retaining wall in Bismarck?
Usually not if it’s 4 feet or less, measured from the bottom of the footing, and doesn’t support a surcharge. That’s the 2021 International Residential Code rule North Dakota adopts. Taller walls and walls holding up a driveway, slope or building need a permit. Confirm with Bismarck Building Inspection at 701-355-1465.
How is retaining wall height measured?
From the bottom of the footing to the top of the wall. For a block wall, that includes the gravel leveling pad and the buried first row. With NCMA’s minimum 6-inch pad and 6 inches of buried block, a wall that shows 3 feet above the lawn already measures 4 feet.
What is a surcharge on a retaining wall?
Extra weight on the soil behind the wall, like a driveway, parked cars, a shed, a slope above or another wall. NCMA also lists snow piled on top of a wall and plows pushing snow into it as loads to design for.
When does a retaining wall need an engineer?
The 2021 IRC requires an engineered design for walls holding back more than 48 inches of unbalanced fill, or walls over 24 inches tall that hold back more than soil. The design must use a 1.5 safety factor against sliding and overturning.
Where should a retaining wall drain pipe go?
NCMA says drain pipes must exit to daylight or connect to an underground drainage system, with outlets protected from crushing or plugging. Send the water to a lower spot on your own lot, away from sidewalks, driveways and neighbors.
Do I need to call 811 before building a retaining wall?
Yes. NDSU Extension says to call 811 or file online at least two full business days before you dig. Private lines, like sprinkler pipes, aren’t marked, so locate those yourself.
Bismarck Landscape
Planning a Wall?
We’ll measure the real height, check what sits above it and plan the drainage before any block goes in. Call Bismarck Landscape.
See our contact options.