Low-lying areas and storm drainage

Parts of Del Mar sit low, near the mouth of the San Dieguito River and the lagoon, and some streets near the beach are close to sea level. During heavy rain, drainage there gets tested. This page is a preparation guide, not a flood map.

Know your risk from official sources

• Look up your address on FEMA's flood maps, which FloodSmart links to.
• Check San Diego County's floodplain information.
• Watch City of Del Mar notices before and during storms.

Prepare

• Clear gutters, downspouts and yard drains.
• Keep valuables and documents off the floor in lower rooms and garages.
• Know how to shut off power at the panel safely.
• Have a plan for where you would go if told to evacuate.
• Review flood insurance; Ready.gov notes it typically takes up to 30 days to start.

During high water

• Follow official alerts.
• Stay out of floodwater. Ready.gov warns six inches of moving water can knock you down.
• Do not touch electrical equipment if it is wet or you are standing in water.

Afterward

Treat water that came in from outside as contaminated. Document, remove soaked porous materials, clean and dry. Full steps in flood cleanup.

Understanding flood risk tools

FEMA's Flood Insurance Rate Maps show areas with a mapped 1 percent annual chance of flooding, often called the 100-year floodplain, along with moderate and low-risk zones. Those maps are a starting point, not a guarantee; FloodSmart notes that flooding happens outside high-risk areas too. San Diego County's flood control resources and the City of Del Mar's notices add local context.

Flood insurance facts

• Most homeowners policies do not cover flood, according to FloodSmart.
• NFIP building coverage goes up to $250,000 for single-family homes; contents up to $100,000.
• Renters and condo owners can buy contents coverage.
• New policies generally take effect after 30 days, with exceptions such as purchases tied to a mortgage.

Making a home more resilient

• Keep utilities such as electrical panels and water heaters elevated where possible.
• Store valuables and documents above floor level in lower rooms and garages.
• Use water-resistant materials in lower areas during remodels.
• Maintain grading and drainage so water moves away from the house.
• Keep a storm kit: flashlight, gloves, boots, plastic sheeting, phone charger.

After high water

Photograph the high-water mark on walls, inside and out. Record which rooms and materials were affected. Remove wet porous materials and dry promptly; floodwater is treated as contaminated.

Storm drains and runoff

Storm drains carry runoff toward creeks, the lagoon and the ocean without treatment, which is why debris, mud and cleanup water should never go into them. Blocked drains on public streets in Del Mar can be reported to the city. On your own property, keep yard drains and swales clear and make sure downspouts discharge away from the foundation.

Coastal flooding versus rain flooding

Low-lying coastal areas can see water from more than one direction: heavy rain overwhelming drainage, river and lagoon water rising, and in some cases high surf and tides. Each scenario has different warning signs and timing. Follow official alerts from the City of Del Mar and San Diego County, and know which kind of water your street has seen before.

A household flood plan

1. Know your evacuation route and where you would go.
2. Keep important documents in a waterproof container above floor level.
3. Photograph your rooms and belongings now for insurance.
4. Know how to shut off electricity and gas safely, and when to leave it to the utility.
5. Plan for pets.

Ready.gov's flood guidance covers preparation, staying safe during a flood, and returning home.

Flood insurance timing

FloodSmart, the National Flood Insurance Program site, says coverage goes into effect 30 days after purchase, with a few exceptions such as buying in connection with a mortgage. If you live near the lagoon or on a low street, the time to look at a policy is well before the rainy season, not when a storm is forecast.

Sources, accessed Oct 16 to 17, 2026: FloodSmart (NFIP) · San Diego County DPW: Flood control · City of Del Mar · Ready.gov: Floods · FloodSmart: Buy a flood insurance policy · City of San Diego: Stormwater