How Tall Can You Build a Retaining Wall Without a Permit in Minnesota?

You're looking at that slope in your backyard thinking about the retaining wall you'd like to build. Maybe you want a level spot for a patio, or you're dealing with erosion, or you just want to create beautiful tiered garden beds.

Then reality hits: Do I need a permit for this? Do I need an engineer? What if I just keep it short?

These are excellent questions, and getting the answers wrong can cost you thousands in fines, force you to tear out your work, and potentially create a liability nightmare if something goes wrong.

Let's talk about retaining wall regulations in Minnesota—specifically, how tall you can build before permits and engineering become requirements, and why these rules exist in the first place.

The Quick Answer (With Important Caveats)

In most Minnesota communities, retaining walls over 3-4 feet in height typically require a building permit and often an engineered design. Walls under this threshold may not require permits, though this varies significantly by jurisdiction.

But here's the critical part: That measurement isn't as simple as it sounds, the rules vary by location, and there are many other factors that can trigger permit requirements even for shorter walls.

Let's break it all down so you can make informed decisions about your property.

Understanding How Wall Height Is Measured

Before we discuss specific thresholds, you need to understand how wall height is measured—because it's not what most homeowners expect.

Measuring from the Base of the Foundation

Wall height is measured from the top of the foundation base (or bottom of the wall) to the top of the wall—not from the ground level you see after the wall is finished.

Here's why this matters:

Imagine you want a 3-foot tall wall. You excavate down 12 inches for the foundation, place the base, then build 36 inches of visible wall above it.

The actual wall height? 4 feet (12 inches foundation below grade + 36 inches visible wall).

That extra foundation depth—which is absolutely necessary for stability and Minnesota's frost conditions—pushes many walls into permit territory even when they don't look that tall above ground.

The "Total Height" vs. "Exposed Height" Confusion

Some municipalities measure "total height" (including buried foundation), others measure "exposed height" (only the visible portion after backfilling). Always clarify with your local building department which measurement method they use.

Tiered Walls: Special Measurement Rules

If you're building multiple walls in tiers (stepped walls), special rules often apply:

• If walls are close together (typically less than twice the height of the lower wall apart), they're often measured as one combined wall
• Example: Two 3-foot walls placed 5 feet apart might be treated as a single 6-foot wall
• This almost always triggers permit and engineering requirements

Minnesota State Building Code vs. Local Ordinances

Here's where it gets complicated: Minnesota doesn't have a single statewide rule for all retaining walls.

State Code Baseline

The Minnesota State Building Code (based on International Building Code) generally requires permits for retaining walls over 4 feet in height that support a surcharge (extra load like driveways, structures, or sloped ground above the wall).

However, retaining walls that don't support surcharges may be exempt from state code requirements.

Local Jurisdictions Rule

Most importantly, local municipalities can—and do—adopt more stringent requirements. Your city or county determines the actual rules that apply to your property.

Common local variations include:

• Height thresholds anywhere from 2 feet to 4 feet
• Different rules for walls near property lines
• Specific engineering requirements
• Additional restrictions near water or wetlands
• Homeowners Association (HOA) rules that exceed city requirements

Permit Requirements by Major Twin Cities Jurisdictions

While you must always verify current requirements with your specific municipality, here are general guidelines for major Twin Cities area communities:

Minneapolis

• Retaining walls over 4 feet typically require building permits
• Engineering may be required depending on wall location and purpose
• Walls supporting surcharges (driveways, structures) have stricter requirements
• Zoning setback requirements apply

St. Paul

• Walls over 3 feet generally require permits
• Engineering stamped plans required for taller walls
• Strict requirements near property lines
• Right-of-way walls have additional regulations

Lakeville

• Walls 4 feet or taller typically need building permits
• Engineering requirements for walls supporting surcharges
• Frost depth considerations (42+ inches) must be addressed
• Additional requirements near city property or easements

Burnsville, Eden Prairie, Woodbury, Eagan

Most suburban Twin Cities communities follow similar patterns:

• 3-4 foot threshold for permit requirements
• Engineering required for taller walls or complex situations
• Stricter rules near property lines and public areas
• HOA restrictions may be more stringent than city requirements

Dakota County, Hennepin County, etc.

Unincorporated areas follow county regulations, which often mirror state code but with local amendments.

CRITICAL: Always check with your specific building department. These are general guidelines only. Requirements change, and your specific property may have unique considerations.

When Engineering Is Required (Even for Short Walls)

Here's what catches many homeowners off guard: Even walls that don't require permits may need professional engineering in certain situations.

Situations That Trigger Engineering Requirements

1. Supporting Surcharges

Any wall supporting extra loads typically needs engineering:

• Driveways or parking areas above the wall
• Structures (sheds, decks, patios) near the wall
• Steep slopes above the wall
• Heavy landscaping or soil loads

2. Poor Soil Conditions

If your site has:

• Soft or unstable soils
• High water table
• Expansive clay soils
• Fill dirt that's not well compacted

3. Height (Even if Below Permit Threshold)

While a 3-foot wall might not legally require engineering, it's often wise to get professional input, especially if it's supporting anything or in a visible location where failure would be expensive.

4. Proximity to Structures or Property Lines

Walls near:

• Your home's foundation
• Neighbors' property
• Public right-of-ways
• Utilities

5. Tiered or Complex Walls

Multiple walls, curves, corners, or unusual site conditions warrant professional design.

The Real Risks of "Going Rogue" Without Permits

Some homeowners think: "If I keep it under 4 feet, I'll just build it myself and avoid the hassle."

Here's what can go wrong:

Legal and Financial Consequences

Code Violations:

• Building inspectors can require you to tear out non-compliant work
• Daily fines until violations are corrected
• Difficulty selling your home (unpermitted work shows up in inspections)

Liability Issues:

• If your wall fails and damages neighbors' property, you're liable
• Homeowners insurance may not cover damage from unpermitted work
• Personal injury liability if someone is hurt by wall failure

Property Value Impact:

• Unpermitted work can reduce property value
• Buyers may require removal or permitting before purchase
• Title insurance issues during sale

Safety Risks

Wall Failure:

• Improperly built walls can collapse, causing:
  • Property damage (yours and neighbors')
  • Soil erosion and drainage problems
  • Injury or death in worst cases

The Most Common Cause of Failure? Improper drainage. This is why professional guidance matters—even DIY homeowners often don't understand how critical drainage is for Minnesota's freeze-thaw conditions.

At Preferred 1 Concrete, we've been building retaining walls in the Twin Cities since 2004, with my father's experience going back to the 1980s. We've seen what happens when walls are built without proper design—and it's never pretty.

What Makes a Retaining Wall Safe and Legal

Understanding what goes into proper wall construction helps you appreciate why regulations exist:

1. Engineered Foundation

In Minnesota, frost penetration reaches 42+ inches deep. Your wall's foundation must:

• Extend below frost line for taller or critical walls
• Be properly sized for the wall load
• Sit on stable, compacted base material
• Remain level despite freeze-thaw cycles

2. Drainage Systems (Non-Negotiable)

Water is the #1 enemy of retaining walls. Proper drainage includes:

• Clean, angular drainage gravel behind the wall (minimum 12 inches)
• Perforated drain pipe at the base with proper slope
• Filter fabric separating drainage gravel from soil
• Surface grading directing water away from the wall

We cannot overstate this: improper drainage causes the vast majority of retaining wall failures, especially in Minnesota's freeze-thaw climate.

3. Proper Backfill and Compaction

• Correct backfill materials (not just excavated soil)
• Compaction in 6-8 inch lifts
• Proper density to prevent settling

4. Wall Construction Quality

• Level, stable base course
• Proper setback (batter) leaning into the slope
• Correct block/stone placement
• Reinforcement when needed (geogrid for taller walls)

5. Frost Considerations

Minnesota's freeze-thaw cycles create unique challenges:

• Ice lenses forming behind walls create enormous pressure
• Water trapped behind walls expands when frozen
• Repeated freezing and thawing progressively damages improperly built walls

The Permit Process: What to Expect

If your wall requires a permit, here's what the process typically involves:

1. Pre-Application Research

• Determine specific requirements for your jurisdiction
• Understand setback requirements from property lines
• Check for easements, utilities, or restrictions

2. Design and Plans

For engineered walls:

• Hire a structural engineer licensed in Minnesota
• Engineer assesses site conditions
• Creates stamped plans specifying materials and construction methods
• Calculations prove the wall can safely handle loads

For non-engineered walls (where allowed):

• Detailed drawings showing dimensions, materials, drainage
• Specifications for foundation depth and preparation

3. Permit Application

• Submit plans to building department
• Pay permit fees (typically $100-$500 depending on project scope)
• Wait for plan review (1-4 weeks typically)

4. Construction and Inspections

• Schedule required inspections (usually foundation and final)
• Inspector verifies work matches approved plans
• Corrections if needed
• Final approval and permit closure

Timeline Expectations

• Simple permits: 2-4 weeks from application to approval
• Complex/engineered walls: 4-8 weeks
• Rush fees may be available for faster processing

When You Can Build Without Permits (Probably)

Based on typical Minnesota regulations, you likely don't need permits if:

Your wall meets ALL of these criteria:

• Total height under 3-4 feet (verify local threshold)
• Not supporting any surcharges (driveways, structures, slopes)
• Not near property lines (typically need 3+ feet setback)
• Not in a sensitive area (wetlands, floodplains, HOAs)
• On stable soils with good drainage
• For landscaping purposes only

Even Then, Consider:

• Consulting a professional for design guidance
• Following construction best practices
• Installing proper drainage systems
• Using quality materials appropriate for Minnesota climate

Professional Installation: Why It Matters

Whether or not you legally need permits, professional installation provides:

Expert Site Assessment

Professional contractors understand:

• Soil conditions and their implications
• Drainage patterns and solutions
• Frost depth requirements for your area
• Minnesota-specific construction challenges

Proper Materials and Techniques

We use:

• Quality blocks or stone appropriate for the application
• Clean, angular drainage gravel (not pea gravel or sand)
• Proper filter fabric specifications
• Correctly sized and sloped drain pipe

Liability Protection

When professionals install your wall:

• They carry insurance for the work
• Quality is guaranteed
• Work can be inspected and approved
• You have recourse if problems arise

Long-Term Performance

Properly installed walls last decades. We've been installing concrete patios, driveways, and retaining walls since 2004, and my father's been doing concrete work since the 1980s. We know what works in Minnesota conditions.

Common Mistakes DIYers Make

Even well-intentioned homeowners make these critical errors:

1. Underestimating Drainage Importance

Using incorrect materials (pea gravel instead of angular stone), skipping the drain pipe, or forgetting filter fabric. Result: wall failure within 3-5 years.

2. Inadequate Foundation

Not going deep enough, insufficient compaction, or building directly on soil instead of prepared base. Result: settling, tilting, or collapse.

3. Poor Backfill Practices

Dumping excavated clay behind the wall, not compacting in lifts, or creating voids. Result: wall movement and eventual failure.

4. Ignoring Frost Depth

Not accounting for Minnesota's 42+ inch frost line. Result: frost heave lifting and destroying the wall.

5. Incorrect Height Measurements

Building what they think is a 3-foot wall that's actually 4+ feet when measured properly. Result: code violations and forced removal.

Making Your Decision: A Framework

Use this decision tree to determine your path forward:

Question 1: How tall is your wall (including foundation)?

• Under 3 feet: Probably no permit needed (verify locally)
• 3-4 feet: Check local requirements
• Over 4 feet: Definitely need permits and likely engineering

Question 2: What's the wall supporting?

• Just landscaping: Lower scrutiny
• Driveway, patio, or structure: Higher requirements
• Near building foundation: Definitely needs engineering

Question 3: What are your soil conditions?

• Rocky, sandy, well-drained: Standard approach
• Clay, wet, or unstable: Professional design recommended

Question 4: What's your risk tolerance?

• Willing to risk violations: Proceed at own risk
• Want it done right: Get permits and professional help
• HOA property: Follow strictest applicable rules

Our Recommendation

At Preferred 1 Concrete, we always recommend:

For walls 3+ feet: Get professional design and proper permits. The peace of mind, liability protection, and long-term performance are worth it.

For walls under 3 feet: At minimum, consult with professionals about design and drainage, even if you're doing the work yourself.

For any wall: Understand that proper drainage is non-negotiable in Minnesota's climate. Cutting corners here guarantees failure.

We don't cut corners and we don't take shortcuts. Our commitment is to projects that last—which means following codes, implementing proper drainage, and building to engineering standards even when we're not strictly required to.

Resources and Next Steps

Contact Your Local Building Department

Twin Cities Area Jurisdictions:

• Minneapolis: (612) 673-3000
• St. Paul: (651) 266-9000
• Lakeville: (952) 985-4400
• Burnsville: (952) 895-4400
• Woodbury: (651) 714-3500
• Eden Prairie: (952) 949-8300

Ask specifically about:

• Height thresholds for permits
• How height is measured
• Engineering requirements
• Setback restrictions
• Estimated timeline and costs

Find Licensed Professionals

For engineering:

• Minnesota Board of Architecture, Engineering, Land Surveying, Landscape Architecture, Geoscience and Interior Design: (651) 296-2388

For installation:

• Look for contractors with:
  • Established local history
  • References from similar projects
  • Understanding of Minnesota-specific requirements
  • Proper licensing and insurance

Ready to Discuss Your Retaining Wall Project?

Whether your wall requires permits or not, starting with professional guidance sets you up for success. At Preferred 1 Concrete, we help Twin Cities homeowners navigate permitting requirements, design walls that last, and install them correctly for Minnesota's challenging conditions.

We've been serving families across the Twin Cities since 2004, building walls that are both beautiful and engineered to stand the test of time. We prioritize exceptional customer service and delivering superior work—and that includes ensuring your project meets all necessary codes and requirements.

Contact us today to discuss your retaining wall project. We really enjoy planning great retaining walls, driveways, sidewalks, and patio layouts, and we'd love to earn your business.

Let's build something great—the right way, with all necessary permits and professional standards in place.

‍