Seawalls in Miami Beach

Rules that set the job

Miami Beach requires owners whose walls let tidal water flow over or through them to correct it, either by raising the wall or adding a retaining wall, and can cite owners with no seawall at all. A permit needs a City building permit with a site plan, structural plans and an elevation certification, plus DERM Coastal Resources approval.[1]

Costs in Miami Beach

The city's 2017 rule of thumb was $1,000 to $1,500 per linear foot to bring an old seawall up to code. The city's own public seawall program had cost $80.3 million as of October 2025.[4][3]

Tide at Government Cut

NOAA's Miami Harbor Entrance gauge at Government Cut, beside South Beach, shows a 2.46 ft mean range and a 2.70 ft great diurnal range, with mean higher high water about 0.33 ft above NAVD 88 (1983 to 2001 epoch). A wall at 5.7 ft NAVD therefore stands roughly 5.4 ft above an average high tide, the margin the City wants for king tides and sea level rise.

The tide also sets how much of the wall can be worked on dry at low water, which changes crew time.[5]

What makes Miami Beach different

The city has about 55 miles of seawall, of which only about 5 miles are publicly owned, so most of it is the responsibility of private owners. Its seawall ordinance dates from Resolution R2016-4009 in May 2016, was strengthened in January 2021 and amended again in July 2025.[1][3]

Groundwater and flooding

The city notes that groundwater rises through the porous bedrock under Miami Beach, so a seawall alone cannot stop flooding. A raised wall stops tidal overtopping; drainage and flood protection handle the rest.[4]

Permits for seawalls in Miami Beach

• City of Miami Beach Building Department: Building permit with a site plan, structural plans and an elevation certification.
• Miami-Dade DERM, Coastal Resources Section: Class I permit or exemption for seawalls, docks and lifts on the island canals and the bay, issued alongside the City permit. Phone (305) 372-6575.
• Florida DEP or South Florida Water Management District: State review where a dock or wall reaches open Biscayne Bay, part of the aquatic preserve, where FDEP's free online self-certification is not available.
• US Army Corps of Engineers, Jacksonville District: Federal authorisation for work in Biscayne Bay and Indian Creek; we confirm the small-project route since SPGP VI's stated July 2026 expiry.

Which permits does seawall work need?

In Miami-Dade, any work in, on, over or upon tidal waters needs a DERM Class I permit under Section 24-48 of the County Code, including inside cities. Minor repairs are exempt, cap and tieback work gets an expedited authorisation, and rebuilding a wall at the mean high water line or up to 18 inches waterward is a short-form permit approved by staff.

The city building department also issues a structural permit. A state exemption does not remove county and city permits: Florida Statute 403.813 says its exemptions do not relieve anyone from county and municipal requirements, so in Miami-Dade a DERM Class I permit still applies.[6][8]

How long does a seawall last?

Fort Lauderdale's seawall ordinance FAQ assumed a design life of about 50 years, and city engineers described a 30 to 50 year lifespan for a wall built today. Salt water, wave action from boat wakes and rising tides shorten that when cracks and failed joints are left open.[9]

Why heights matter now

Cities are raising the bar. Miami Beach requires new and substantially repaired seawalls to reach 5.7 ft NAVD, Coral Gables sets bulkheads at a minimum of 6 ft NGVD 1929, and Fort Lauderdale requires 5 ft NAVD. A repair that triggers these rules can turn into a raising job, so we check the local standard before we price.[1][10][11]

Frequently asked questions