Fence on a Retaining Wall: Georgia Rules

Can I build a fence on top of a retaining wall? Often yes, but rules vary. Many height caps leave retaining walls out, and no code we read says how a city counts a fence set on top of a wall. Acworth requires a fence of 36 inches or more on walls 4 feet or higher. Walls over 3 feet 11 inches (Duluth), 4 feet (Flowery Branch pool rules) or 6 feet (Forsyth County) can need a permit. Ask your city.

Last updated: November 2026.

Why a fence on a wall can end up taller than it looks

A retaining wall holds soil back on one side, and the fence stands on top of it. From the low side, your neighbor or the street sees both heights added together, so a 6-foot fence on a 4-foot wall looks like a 10-foot fence. Two things make this tricky:

Many fence caps leave retaining walls out. Several codes write the limit as "other than a retaining wall." Some of those places have separate wall rules, and in others the fence section we read has none, so ask where the wall is covered. The fence on top is still a fence, and no code we read says plainly how the two are counted together.
Height starts from different places. Forsyth County measures a retaining wall from the bottom of the footing, so part of the wall is underground. Cobb County measures the exposed part from the neighbor's side. Roswell measures a fence from the property's grade. Ask which starting point your city will use. Several places also set a wall height, from 3 feet 11 inches up to 6 feet, where a separate permit or an engineer comes in. The numbers are below.

Forsyth County and Cobb County

These apply in the unincorporated parts of each county, not inside a city. Many Cumming addresses are in unincorporated Forsyth County, and East Cobb is under Cobb County, so confirm which covers your parcel.

Forsyth County. Section 16-4.13 of the county's Unified Development Code requires a building permit for fences and walls over six feet. For retaining walls it says that, regardless of height, they are permitted in the setback, and that those over six feet, measured from the bottom of the footing to the top of the wall, require a permit and must be engineered. Terraced walls spaced farther apart than the tallest section is high count as separate walls. Agricultural lots and lots outside a final platted subdivision are exempt from this section, so ask the county which rules apply. It does not say how a fence on top of a wall is counted.

Cobb County. Section 134-267(b) of the zoning code caps a fence or freestanding wall, other than a retaining wall, at eight feet, and at six feet next to a public road or in front of or beside the house in a residential district. Fence height includes posts and ornaments and is measured from the existing grade, and up to six inches of backfill counts toward it. The limit must be met on both sides of the fence. Retaining walls on residential lots, other than in subdivisions still under construction, have their own rule. The exposed part of the wall, measured from the neighbor's side, cannot exceed six feet within five feet of the property line. The limit can rise by five feet for each additional five feet the wall sits back, if a landscape buffer is provided and approved by county staff. Tiered walls must be at least five feet apart. The section does not say how it counts a fence set on a wall, so ask the county. See our East Cobb page.

Wall permit rules by city

Duluth. Section 304.02 prohibits timber retaining walls and says all walls over 3 feet 11 inches need a separate review and permit. See our Duluth guide.
Flowery Branch. The city's pool section (11.10) says a retaining wall over 4 feet needs a separate permit and an engineer. The note sits in the pool rules, so ask if it applies to a wall away from a pool. The fence section (11.6) does not say how height is counted on a retaining wall. See our Flowery Branch guide.
Alpharetta. The city says retaining walls over 4 feet must be engineered and permitted, and so must a shorter wall with a surcharge to the top of the wall. A surcharge is extra weight on the soil behind the wall. See our Alpharetta guide.
Milton. Under Section 9.3.7, a wall retaining 4 or more feet of unbalanced fill needs a permit, and a wall 4 feet or taller may not sit within 10 feet of the front property line. Walls 4 feet or taller must provide fall protection, which the code says can include permanent landscaping or fencing. On lots in the rural viewshed, retaining walls are barred within 60 feet of the right-of-way. See our Milton guide.
Dawsonville and Dawson County. The City of Dawsonville's forms page lists a Development / Retaining Wall Application, and we did not find a wall height there. Dawson County's list of typical projects that need a county permit, which it says is not comprehensive, includes retaining walls over 4 feet tall. See our Dawsonville guide.
Cumming. The city's permit form is titled "Application for Fence/Retaining Wall Permit," and it says inspections are required. We did not find a wall height where the permit starts. See our Cumming guide.
Gainesville. Section 16-6-3 lists retaining walls not over 4 feet, measured from the bottom of the footing to the top of the wall, among the things that need no building permit, unless the wall supports a surcharge or holds certain liquids. The same list says fences not over 7 feet need none, while the city's Building Permit page says 6 feet, so ask which number applies. See our Gainesville guide.

Where the fence rules mention retaining walls

Cumming. Section 113-243 caps a fence or wall at eight feet, "except for required retaining walls," and keeps it five feet from a public right-of-way, again with an exception for required retaining walls. We did not find "required" defined, so ask whether your wall counts.
Dawsonville. Section 713 sets a ten-foot cap, except for required retaining walls.
Kennesaw. The eight-foot cap in rear and side yards does not apply to retaining walls, among a few other structures.
Gainesville. Section 13-1-9 sets eight feet for a fence or freestanding wall in a yard, other than a retaining wall or a recreational court fence.
Marietta. Section 710.04 says retaining walls are not subject to it. The same subsection says all properties must meet Section 716.04, which we did not read.
Cherokee County. Section 5.7 caps a fence or freestanding wall other than a retaining wall at eight feet, in the unincorporated areas near Woodstock and Canton.
Suwanee. Section 610 says the setback rules do not prohibit any necessary retaining wall. Its eight-foot cap on a fence or wall has no retaining wall exception in the text we read, and the section does not say if a retaining wall counts toward that cap.
Sugar Hill. The other direction. The residential maximum is eight feet, and engineered retaining walls higher than eight feet may be permitted with an administrative variance.

Leaving a wall out of a cap does not mean the fence on top of it is free of limits. Ask each city how the two combine.

Acworth: a fence on top of a tall wall is required

Acworth is the only code we found that names a fence as a requirement on a tall wall. Section 73-8.2 says a retaining wall four feet or higher must incorporate at the top a fence not less than 36 inches. A 4-foot wall with a 36-inch fence adds up to about 7 feet if the wall's height is measured from the low side, and the code does not say how it is measured. Milton also requires fall protection on walls 4 feet or taller (Section 9.3.7), and says that can include permanent landscaping or fencing. See our Acworth guide.

Roswell and Sandy Springs: how height is counted

Roswell. Section 10.2.10 says fence height is measured from the subject property's grade to the highest point, and that a fence may not retain dirt. If the ground behind your fence line needs holding back, that is a retaining wall question for the city. The code does not say how it counts a fence on a wall. See our Roswell guide.

Sandy Springs. Section 8.3.10 measures height from finished grade to the highest point of a fence or wall between columns or posts, and side and rear yards can go to 8 feet above grade. For retaining walls it points to Section 9.4.3, which we did not read, so ask the city how it treats a fence on or near a wall. See our Sandy Springs guide.

Where we did not find a retaining wall rule

We did not find a retaining wall statement in the fence sections we read for Canton, Woodstock or Buford. Buford caps a wall or fence at six feet in a front or side yard in residential districts and does not say whether a retaining wall counts. We have not read Johns Creek's retaining wall rules. In any of these places, ask the city before you plan a fence on a wall. See the Canton, Woodstock and Buford guides.

What to ask before you build

Does my wall need its own permit, and at what height? Does it need an engineer?
Is my fence counted by itself, or added to the wall? Is height measured from the footing, my grade or my neighbor's grade?
Is there a minimum fence on top of the wall, or a limit on how close the wall can sit to the property line?
Does one permit cover the wall and the fence, or are they two steps?
Does my HOA add its own rule? We assist with HOA approval forms, and approval is always your HOA's decision. See our HOA fence approval guide.

Ask for the answer in writing, and bring your survey and any wall drawings.

How we plan a fence near a wall

We look at the wall, the slope and your survey before we give you a written estimate, and we tell you honestly if a plan may run into a rule. Where the ground drops in distinct levels, such as at a retaining wall, we often step the fence instead of racking it. Our racked versus stepped fence guide explains the difference. In some places a retaining wall needs its own permit and an engineer, separate from the fence, so ask the city before you plan around it. Before we dig, we call 811 for you, and crews mark the buried gas and power lines.

Rules change and every lot is different. Confirm the details for your yard with the city or county before you order materials. See our permit and HOA checklist.

Common questions

Does a retaining wall count toward the fence height limit?

In many places the fence cap leaves retaining walls out, including Cumming and Dawsonville (which leave out only required retaining walls), Kennesaw, Gainesville, Acworth, Marietta, Cobb County and Cherokee County. That does not make the fence on top free of limits. None of the codes we read says how the two are counted together, so ask your city.

At what height does a retaining wall need a permit or an engineer?

It depends on the place. Flowery Branch (in its pool rules), Alpharetta and Dawson County name walls over 4 feet, and Flowery Branch and Alpharetta add an engineer. Milton requires a permit for a wall retaining 4 or more feet of unbalanced fill. Duluth names 3 feet 11 inches. Forsyth County says over 6 feet, measured from the bottom of the footing, needs a permit and an engineer. Cumming and the City of Dawsonville have wall permit forms, and we did not find a height.

Does Acworth really require a fence on top of a retaining wall?

Yes for walls four feet or higher. The zoning ordinance says such a wall must incorporate at the top a fence not less than 36 inches. Ask the city what it expects the fence to look like.

Can a fence hold back dirt?

Roswell's Section 10.2.10 says a fence may not retain dirt. We did not confirm whether that section applies to every single-family fence, so ask the city. We did not read the same sentence in the other codes. If the ground behind your fence line needs holding back, ask your city about a retaining wall.

How is the height of a fence on a wall measured?

No code we read says how a fence on top of a wall is measured, and codes start from different places. Forsyth County counts a wall from the bottom of the footing, and Gainesville does the same for its building-permit exemption for walls not over 4 feet. Cobb County measures the exposed wall from the neighbor's side. Roswell measures from the property's grade, and Sandy Springs from finished grade. Ask which one your city uses.

Do I still need HOA approval if the city allows the fence?

Possibly. HOA approval is separate from any city or county permit. We assist with HOA approval forms, and approval is always the HOA's decision.

Fences on Retaining Walls in North Georgia: What Each City and County Says