Waterfront Property Buyer Due Diligence
Buying a Waterfront Property? Consult a Coastal Engineer Before You Close
An oceanfront or bayfront home can look sound while its seawall, revetment, dock, piles, or deck needs major work. An engineering assessment during the purchase period can help you understand coastal flooding, wave exposure, shoreline structures, and potential future costs.
A Buyer Due Diligence Example
Two Dana Point Properties, Two Decisions Before Closing
In February and June 2025, a prospective buyer contacted us through his real estate agent about two properties in Dana Point. One had a timber seawall; the other had a rock revetment. We were asked to assess the shoreline protection before the buyer completed either purchase.
Our review identified both properties in FEMA Zone VE, a coastal high-hazard area associated with the 1%-annual-chance flood and wave action. We explained that a 1%-annual-chance flood level has about a 26% chance of being equaled or exceeded at least once over 30 years. That statistical figure describes the flood event, not a prediction that either house would sustain damage.
The revetment's visible configuration and condition also raised engineering concerns. In the public records available to us, we could not locate coastal authorization for that structure. We advised the buyer to confirm its permit status with the responsible agencies; an unauthorized structure could create permitting, modification, removal, or enforcement exposure.
The buyer decided not to proceed with either purchase. In September 2026, high surf damaged homes in the Dana Point. We cannot attribute damage at either specific property to our findings, but the episode shows why coastal conditions deserve attention before closing. The properties under consideration each had an asking price above $10 million, according to the buyer.
Each property requires its own site-specific assessment.
Shoreline Protection
Seawall and Bulkhead Condition
Cracking, spalling, corrosion, wall movement, deteriorated timber, failed connections, backfill loss, and scour can signal repair needs that are easy to miss from the residence. We review accessible panels, coping, piles, walers, tiebacks, drainage, and the beach or dredge-line condition as the scope and tide permit.
Learn about seawall assessmentRevetment Condition
Rock protection should be reviewed for displaced or undersized armor, slope and crest condition, toe scour, settlement, exposed filter material, flanking, and evidence of lost soil behind the system. A visual review may identify concerns; concealed layers and design adequacy can require additional investigation.
Explore revetment engineeringWater Levels and Waves
FEMA Flood Zone and Base Flood Elevation
Compare the mapped flood zone and Base Flood Elevation (BFE) with surveyed finished-floor, site, and seawall elevations using a consistent vertical datum such as NAVD88. The 1%-annual-chance designation does not mean a flood occurs only once in a century, and mapped BFE alone does not describe every site-specific hazard.
Consider high tides, storm water levels, drainage, low-lying areas, and how flooding may reach the building. Current elevation information and property-specific analysis matter more than a map designation in isolation.
Wave Runup and Overtopping
Waves can run up a beach, revetment, bluff, or seawall and pass over a protective structure. For exposed sites, an appropriate wave runup or overtopping analysis can help assess the risk to decks, patios, backfill, foundations, and lower floors under selected water-level and wave scenarios.
Explore wave runup analysisWaterfront Improvements
Marina, Dock, and Marine Piles
Review the accessible condition of floating docks, gangways, pile guides, decking, floats, fenders, and marine piles. Cracking, corrosion, decay, impact damage, hardware deterioration, and loss of section may affect serviceability and future replacement costs. Underwater or concealed components may need a separate specialist review.
See floating dock servicesCantilevered Waterfront Decks
Salt air, spray, and waves can damage concrete, reinforcing steel, structural steel, wood framing, connectors, and guardrail anchorage. A cantilevered deck deserves careful attention at its supports and connection to the building, especially where the framing is hard to access above the water.
Permit History
Check Coastal Development Records
Compare available local and California Coastal Commission records with existing seawalls, revetments, docks, piles, decks, stairs, grading, and additions. A building permit does not by itself establish coastal authorization. If records are missing or inconsistent, ask the responsible agency to clarify the status before closing.
Depending on the facts, unpermitted development may require an after-the-fact permit, modification, restoration, removal, or enforcement response. A records search cannot guarantee that all prior work was permitted or that an apparent absence of records proves a violation.
Long-Term Planning
Understand Future Coastal Costs
Evaluate sea-level rise, shoreline erosion, beach or bluff change, and the possible need for future shoreline repair. The purchase budget may also need room for surveys, engineering studies, environmental work, construction, and permit processing.
A written assessment can identify observed concerns and practical next steps, including where a more detailed Coastal Hazard Analysis, underwater review, testing, or agency consultation is warranted.
Know What You Are Buying Before You Close
A conventional home review rarely covers the complete coastal system. We provide professional engineering assessments for Southern California oceanfront, bayfront, harbor, and marina properties, from Santa Barbara to San Diego.
Seawalls • Bulkheads • Revetments • FEMA BFE • Wave Runup • Overtopping • Docks • Marine Piles • Cantilevered Decks • Coastal Permit Records
Reference information: FEMA Zone VE and California Coastal Commission Enforcement Program. Flood mapping and permit status should be checked for the specific parcel.