Bulkhead vs. Seawall: What Is the Difference?

The Short Answer: Soil Versus Waves

The cleanest way to separate the two is by the job each one does. A shoreline stabilization guide published by NOAA and the U.S. Army Corps of Engineers describes a bulkhead as a vertical retaining wall, parallel to the shoreline, intended to hold soil in place and allow for a stable shoreline. It describes a seawall as a wall, vertical or sloped, that absorbs and limits the impact of large waves and directs flow away from land, suited to areas highly vulnerable to storm surge and wave forces. The same guide notes that bulkheads are also used in high-energy settings and working waterfronts such as ship and ferry docks, so the difference lies in each wall's primary job rather than a strict rule about where each one can go.

Florida's coastal construction rules lean the same way. Rule 62B-33.002 of the Florida Administrative Code defines a seawall as a structure separating land from water areas, primarily designed to prevent erosion and other damage due to wave or current action. Both are classed as rigid coastal structures, alongside revetments, groins and jetties.

Put simply: a bulkhead's main enemy is the weight of wet soil pushing toward the water. A seawall has that problem too, plus repeated wave impact, water coming over the top, and scour at its base.

Why Florida Uses the Words Interchangeably

In everyday Florida usage, almost any vertical wall at the water's edge is called a seawall, including walls on quiet dead-end canals that engineers would describe as bulkheads. Official documents reflect that habit:

• Key Colony Beach's Seawall Owner's Manual defines a seawall simply as a structure that separates a body of water from adjacent land, built from panels or sheet piling, a concrete cap and tie-back rods anchored to a deadman. That is the classic anchored bulkhead, under the name seawall.
• Palm Coast's technical manual draws the line by location rather than job: walls set at or below about half a foot under mean sea level (feet wet) are seawalls, walls set above the mean high water line (feet dry) are bulkheads, and the manual says both are vertical bulkheads constructed the same way.
• State law mostly says seawall. Section 403.813, Florida Statutes, refers to the restoration of seawalls, and section 373.414 sets rules for vertical seawalls in estuaries and lagoons, whatever the wall's exposure.

Coastal agencies elsewhere have pointed out the same confusion. Rhode Island's coastal management council notes that the terms seawall, revetment and bulkhead are frequently used interchangeably, yet shouldn't be. For a Florida owner the practical lesson is to describe the structure and its exposure when you talk to a contractor or an agency, rather than relying on either word.

Side-by-Side Comparison

Same Parts, Different Demands

Physically, most Florida bulkheads and seawalls are assembled from the same components. What changes on an exposed shoreline is how big and how well protected each part has to be.

• Panels or sheet piles extend from the yard to below the bottom of the waterway. Key Colony Beach's manual describes reinforced concrete panels about 6 inches thick, 5 to 8 feet wide and 10 to 16 feet long, or PVC, composite or metal sheet piling instead.
• A cap, usually reinforced concrete, ties the top of the wall together.
• Tie-back rods and a deadman keep the wall from rotating into the water. The manual places the deadman roughly 10 to 12 feet back in the yard.
• Weep holes, French drains and filter fabric relieve water pressure behind the wall while keeping fill from washing out.
• Toe support, from the berm of soil in front of the wall or from riprap, keeps the bottom of the wall from kicking out.

On a seawall that takes real wave action, the toe and the area right behind the cap become the critical zones: waves scour the bottom, and water that comes over the top can wash out fill from behind. That is why exposed walls often get deeper embedment, heavier toe protection and more attention to cap height.

Where Revetments Fit

A revetment is a third option that gets lumped in with both. Instead of a vertical face, it is a sloped layer of stone or other armor laid over the bank. The NOAA and Corps guide describes it as a structure that lays over the slope of a shoreline and protects it from erosion and waves, and Florida's Rule 62B-33.002 defines it as a sloped facing structure made of armoring material.

Revetments also show up in combination with vertical walls. Florida's Rule 62-330.431 grants a general permit for riprap at the toe of an existing vertical seawall when the slope is no steeper than two horizontal to one vertical and it reaches no more than 10 feet from the toe, using natural boulders or clean concrete rubble one to three feet across, with conditions. In estuaries and lagoons, section 373.414 says that when an existing vertical seawall is repaired or replaced under a permit, the agency shall generally require riprap facing unless an exception applies. See Riprap Revetments for more.

How to Tell What Your Shoreline Needs

A wall on a quiet canal and a wall facing a wide reach of water can look identical from the yard. The second one usually needs more height, more embedment and better toe protection. In Northeast Florida, for example, FWC's regional mapping describes the lower St. Johns River as narrow, deep, fast-flowing and actively tidal from Mayport to downtown Jacksonville, wide, shallow and slow from there to Doctors Lake, and nearly fresh with weak tides beyond, so two riverfront lots in the same county can face very different conditions. See Seawall Construction and Bulkhead Construction.

Why the Label Matters for Permits and Paperwork

Permit rules are written around specific words and locations, so it pays to describe your project precisely. A few examples of how Florida rules use the terms:

• The state exemption in section 403.813(1)(e) covers restoration of seawalls at their previous locations or upland of, or within 18 inches waterward of, their previous locations, and says it does not exempt work from coastal permitting under chapter 161.
• Seaward of the Coastal Construction Control Line, Rule 62B-33.002 groups seawalls, bulkheads, revetments and similar structures as armoring, and separately defines minor reconstruction, major reconstruction and armoring replacement.
• Local building departments may use their own definitions and design standards. Palm Coast, for example, sets a cap elevation, approved materials and minimum end returns for walls on its saltwater canals.

Key Colony Beach's manual adds a reminder that a seawall can have a legal role as well as a physical one there: it can mark the boundary between private land and sovereign submerged lands and help define a waterway's width or a permitted dock. Before any work, confirm requirements with the agencies involved. The Florida seawall permits overview explains who regulates what.