Seawall height and code guidance
Find the wall measurement you need and check local height rules before raising or replacing your seawall.
- Top of the capMeasured from a fixed survey reference.
- WaterlineRises and falls with tides and weather.
- Survey reference (datum)A named reference, such as NAVD88.
Use the survey reference printed beside the elevation.
How high should your seawall be?
Your city or county may set a lowest or highest allowed elevation for the top of the wall. The rules can change with the property’s location and the work planned. Drainage, flooding and neighboring properties also affect the design.
For local height rules, use the top-of-cap elevation on your survey. This is the top of the wall measured from a fixed survey reference. It is different from the wall’s bottom-to-top height or the water level.
Find these two items on your survey.
Find the elevation for the top of the seawall cap and the survey reference used with it. The example below shows what to look for.
Seawall cap elevation
- Top of seawall cap
- 6.00 ft
- Survey reference (datum)
- NAVD88
This example shows 6.00 ft NAVD88. Use the number and reference on your own survey.
Match the value and the reference.
- The elevation: use the number for the top of the wall cap, not a building floor, water depth or the wall’s full height.
- The reference: copy the name beside the elevation, such as NAVD88 or NGVD29. You can compare elevations only when they use the same reference.
- Cannot find both? Choose “No / not sure” in the checker. Ask a surveyor to help find them; measuring from the water will give a different result.
What does NAVD88 mean?
NAVD88 is a fixed survey reference used to measure elevations, like a shared zero point. Another survey may use NGVD29 or a tide-based reference. To compare two elevations, they must use the same reference. A surveyor can help if the references differ. Read NOAA’s explanation of survey references.
Look for the seawall cap elevation on your survey or final construction plans. A flood certificate may show only the building’s elevation. If the wall measurement is missing, ask a surveyor; you do not need to measure beside the water.
Repair, replacement and permits
Before raising or replacing the wall, ask the permitting office which rules apply to the work. An engineer can check whether the existing wall, supports and drainage can handle the change. A higher wall can also change where rainwater flows.
Use the permit guide to find the local, Florida DEP and U.S. Army Corps of Engineers contacts. Describe your location and planned work and ask which permits you need. Florida DEP’s application instructions explain the information needed for shoreline projects.
Common questions
How do I plan a change in wall height?
Start with your survey, the wall’s condition and the change you want to make. An engineer can check the supports, drainage and effects on nearby properties. Tell us about your plans and we’ll help you prepare the next step.
Is maximum height the height I must build?
A maximum is the highest allowed elevation, not a target you must build to. Ask your permitting office whether there is also a minimum for your property.
What if I do not know the elevation?
You can start with the property address and what you want to change. A surveyor can identify the top-of-cap elevation and its reference on your survey.
Can an existing seawall be raised?
An engineer needs to check the wall, supports and drainage before recommending a height change. The right approach may involve modifying the wall or replacing parts of it.
Does meeting a number mean the wall is safe?
Height is only one part of the wall’s condition. The supports, drainage and signs of damage also matter. Use the warning-sign check to prepare for an assessment.
How can I get help with the height?
Tell us the property’s city or county and what you want to change. Discuss the next steps, including whether you need a survey or seawall assessment. Confirm any service details and price before going ahead.
Treasure Coast: no published seawall height minimum found
Unlike some South Florida cities, we found no adopted minimum seawall or tidal-barrier elevation in Port St. Lucie, St. Lucie County, Martin County, Stuart or Sewall’s Point code research. Building elevation rules do apply: in Port St. Lucie and unincorporated Martin County, substantially improved or damaged buildings must sit at least 1 foot above base flood elevation. Ask the permitting office whether any wall-height condition applies to your project before you design a new cap.
Martin County’s own MacArthur Boulevard resilience project at Bathtub Reef Beach used a buried sheet-pile seawall with a new cap at elevation 10.0 and raised the road to at least 5.25 feet. That is a public beachfront design, not a residential standard.
Post-Storm Recovery Permitting Guide · Flood Zones and Flood Protection · MacArthur Blvd (Resilient Martin)
Tide datums for local surveys
| Station | Mean tide range | Mean high water vs. NAVD88 |
|---|---|---|
North Fork, St. Lucie River (8722334) | 0.98 ft | −0.43 ft |
Stuart (8722357) | 0.86 ft | −0.39 ft |
Fort Pierce Inlet (8722213) | 2.02 ft | −0.14 ft |
St. Lucie Inlet, South Point (8722375) | 1.99 ft | −0.23 ft |
NOAA’s nearest long-term sea-level trend station, Lake Worth Pier, shows a rise of 1.62 inches per decade since 1970. St. Lucie County’s 2025 vulnerability assessment projects that, under its intermediate-high scenario, tides reached on 150 or more days a year rise to 1.3 ft NAVD88 by 2040.
Datums for 8722334, North Fork (St. Lucie River) FL · Datums for 8722357, Stuart FL · Datums for 8722213, Fort Pierce Inlet, Binney Dock FL · Datums for 8722375, South Point, St. Lucie Inlet FL · Relative Sea Level Trend 8722670 Lake Worth Pier, Florida · St. Lucie County Regional Resilience Vulnerability Assessment - Final Report
Show sourcesHide sources
- Post-Storm Recovery Permitting GuideSource reviewed 2026-10-25
- Flood Zones and Flood ProtectionSource reviewed 2026-10-25
- MacArthur Blvd (Resilient Martin)Source reviewed 2026-10-25
- Datums for 8722334, North Fork (St. Lucie River) FLSource reviewed 2026-10-25
- Datums for 8722357, Stuart FLSource reviewed 2026-10-25
- Datums for 8722213, Fort Pierce Inlet, Binney Dock FLSource reviewed 2026-10-25
- Datums for 8722375, South Point, St. Lucie Inlet FLSource reviewed 2026-10-25
- Relative Sea Level Trend 8722670 Lake Worth Pier, FloridaSource reviewed 2026-10-25
- St. Lucie County Regional Resilience Vulnerability Assessment - Final ReportSource reviewed 2026-10-25
Ask about local requirements
Identify the property and the question to resolve. Keep any available survey with your planning notes.