Marco Island Seawall Height & Survey Guidance
Use a surveyed top-of-cap elevation with its named datum. Confirm the current rule for the parcel and proposed work with the city.
- 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.
The current numerical rule still needs confirmation
A city-hosted 2018 code packet states a 3.2–4.2-foot NAVD cap range and conditions for transitions between walls. That is a historical reference. The current codified text could not be independently checked during this review, so this site does not present those numbers as today’s compliance test.
Ask Building Services for the current section, amendments, applicability to existing walls and the trigger for your proposed work. Obtain the determination before selecting a cap elevation or signing a change order.
Historical city seawall code packet (2018) · Marco Island Building Services
Read the elevation and the reference together
Form 31 requires a completion survey showing wall height in NAVD88. That is an elevation relative to a survey datum, not the exposed distance above today’s water. Copy both the top-of-cap number and its reference into the project brief.
Do not compare a cap elevation with a building’s finished floor or use a generic offset to convert an old survey. NOAA distinguishes survey datums; a surveyor should resolve incompatible references.
- Top-of-cap elevation
- The surveyed level of the cap relative to its stated datum. Ask the surveyor to identify the measurement location and reference.
- Visible height above water
- A distance to the water surface at a particular time. It changes with the water and does not supply the surveyed cap elevation.
- Older drawing
- Read the original datum and units. Ask a surveyor to reconcile it with the current survey before comparing numbers.
Tide records answer a different question
NOAA’s Caxambas Pass station 8724967 datum sheet uses historical observations from 1976–1979 and the 1983–2001 tidal epoch. It is not a live water-level sensor reading or a parcel-specific conversion.
A higher wall may affect drainage and adjoining connections. Ask the engineer to evaluate the whole system and the city to confirm the applicable height and alignment requirements. Nearby county waterfronts require their own jurisdiction review.
Before raising a cap, ask how the proposed elevation affects yard drainage, wall connections, dock access and neighboring conditions. Keep the city’s determination, engineer’s design and survey together. A photograph of a higher neighboring wall does not establish what your parcel may build.
NOAA Caxambas Pass benchmark sheet · Marco Island Seawall Owner’s Manual (April 2014)
Show sourcesHide sources
- Historical city seawall code packet (2018)Source reviewed 2026-10-25
- Marco Island Building ServicesSource reviewed 2026-10-25
- City seawall permit application — Form 31Source reviewed 2026-10-25
- NOAA datum FAQSource reviewed 2026-10-25
- NOAA Caxambas Pass benchmark sheetSource reviewed 2026-10-25
- Marco Island Seawall Owner’s Manual (April 2014)Source reviewed 2026-10-25
Keep your project details together
Use these questions when you speak with a professional. If you send the form below, we pass your details to a local marine contractor.