Signs Your Seawall Is Failing: Leaning, Cracks, Sinkholes and Clogged Weep Holes

A seawall holds back the water in front of it and the soil behind it. Every tide pushes water into the fill behind the wall and then lets it drain out. If the wall has an open joint, a crack, a clogged weep hole or a gap under the toe, the water carries fine sand with it on the way out. Engineers describe upland sinkholes as the result of washout of soil through the seawall. [cumminscederberg.com]

Fort Lauderdale's Riverwalk showed the pattern in 2026: a section collapsed, and the cause was traced to an old seawall that allowed soil under the pavers to escape into the river, creating holes and cavities. [cbsnews.com]

When water cannot drain after a high tide or heavy rain, it builds hydrostatic pressure behind the wall. Clogged weep holes and poor drainage add load the wall was never designed for. [dalinghausconstruction.com]

Salt water works on the steel inside the cap and tie-backs, and boat wake on busy canals adds cycles of loading that pull at the toe and the joints. None of this is a reason to panic; it is a reason to look.

Look on the land side first. A dimple, a soft spot, a hole that appears after rain or a king tide, pavers that rock, or a lawn that will not stay level along the wall all mean the same thing: soil is leaving through the wall or under it. The surface holds until the void below is big enough to collapse, so a small dip can become a hole overnight.

Owners on boating forums describe exactly this: a sinkhole on the yard side of the cap where soil was seeping through a seam below the mud line, which is why the leak is not visible from the dock. [thehulltruth.com]

Do not just fill the hole with dirt. It hides the symptom and the next tide keeps pulling fill out. Engineers use probing along the seabed and observations above and below water to find where the soil is escaping; only then does it make sense to seal the path and restore the backfill. [cumminscederberg.com]

• Vertical or horizontal cracks that are getting longer or wider. Hairline shrinkage cracks are common in concrete; widening cracks are not. [heliconusa.com]
• Rust streaks running down the face. Salt water has reached the reinforcing steel, and rusting steel expands and pushes the concrete off. Exposed rebar means that stage is already here. [heliconusa.com]
• A gap opening between the cap and the panels, or between the cap and the dock. The cap ties the panels together; when it separates, panels can move on their own. [heliconusa.com]
• Standing water behind the wall after rain or high tide. The wall is holding water in instead of letting it drain. [heliconusa.com]
• A sag or slope along the top of the cap when you sight down its length. Caps are poured level; a low spot usually means the panels under it have settled or the fill has left.

Rotation, a wall tipping toward the water, is one of the four triggers engineers name for a professional inspection. It usually means the tie-backs that hold the top of the wall to an anchor buried in the yard have corroded, stretched or pulled loose, or that the toe has lost the soil that braced it. [cumminscederberg.com]

A leaning wall is a structural problem, not a sealing problem. Foam injection or crack sealing can stop soil loss behind a sound wall, but it does not pull a wall upright or replace a failed tie-back rod. The fix is new tie-backs and anchors, a new cap, or panel replacement, and an inspection decides which. Keep vehicles and new loads off the yard along the wall until someone has looked at it, and photograph the lean from the same spot each week; movement between photos is the signal to stop waiting. See the repair versus replace guide for how that decision is made.

Weep holes are the small openings through the wall that let groundwater and rain drain to the water side. Behind each one there should be a filter, usually fabric or a gravel pocket, that lets water through and keeps sand back. Over time, weep holes clog with sediment and marine growth, so water pressure builds behind the wall after every high tide and every heavy rain. [dalinghausconstruction.com]

The opposite failure is just as common: the filter has rotted or was never there, so the weep hole drains fine but carries sand out with the water. Both show up the same way on land, as settlement and holes along the wall. [dalinghausconstruction.com]

The American Society of Civil Engineers recommends that coastal structures be inspected a minimum of once every five years; Langley Coastal recommends every one to two years for South Florida seawalls, and sooner after a storm. Many Southeast Florida seawalls built in the 1950s and 1960s are now over 60 years old, and repairs on those walls are typically less expensive than replacement when they are caught early. [cumminscederberg.com]

A proper inspection documents deterioration above and below water: removing marine growth in the tidal zone to see the concrete, probing along the seabed at the toe, and checking the yard for settlement. [cumminscederberg.com]

Langley Coastal Construction's seawall inspections include underwater photos and video. Below the waterline is where most leaks start: open panel joints, a scoured toe, a seam below the mud line, or a footer with voids under it. The report shows you what the wall looks like down there and which repair fits, whether that is hydraulic cement crack repair, forms-and-rebar work on the cap, or NCFI Terra-Lok foam injection to stop water and soil moving through fractures and voids. Details are on the seawall repair page.