Photo: Taylorj661 · Public domainOn FEMA’s figures, San Marcos faces more hazard damage per building than 74% of U.S. towns, mostly from river and rain flooding
On FEMA’s National Risk Index, San Marcos gets a C for hazard risk: higher expected damage per building than 74% of U.S. towns, #130 of 847 in California. Most of that expected damage is river and rain flooding (72%), then earthquakes (18%). Flood insurance has paid 18 claims here since 1978.
Graded on FEMA’s expected yearly building damage per dollar of building value (NRI v1.20, December 2025), weighted by where residents live; flood claims are shown, not graded. How hazard risk is graded
What San Marcos faces
Each hazard’s share of the building damage FEMA expects here, and how its rate compares with the rest of the country.
River and rain flooding
Earthquakes
Wildfire
Shares are of FEMA’s expected building damage, the measure the grade uses; ranks compare each hazard’s building-damage rate with all 85,154 U.S. census tracts. In FEMA’s terms, river and rain flooding is FEMA’s “Inland Flooding” (rivers and streams overflowing their banks, or rain overwhelming drainage). FEMA defines coastal flooding as high or rising tides and storm surge, so surge damage is counted there. Drought isn’t listed: FEMA counts its losses in crops only.
What’s behind San Marcos’ grade
River and rain flooding is 72% of the building damage FEMA expects in San Marcos, and San Marcos’ rate of river and rain flooding damage is higher than 78% of U.S. census tracts. Wildfire adds 9%, at a rate in the top 5% of U.S. census tracts.
C #130 of 847 in California; higher expected damage per building than 74% of U.S. towns (21,298).
San Marcos’ residents live in 25 census tracts; FEMA’s figures are combined by where they live.
The typical California town has higher expected damage than 92% of U.S. towns; within the state, San Marcos has less expected damage per building than 85% of California towns.
In dollars, FEMA expects about $34.4M a year in losses across San Marcos: $32.2M to buildings, the rest to people and crops.
Does San Marcos flood? Sometimes: 18 flood claims since 1978
Every paid claim on a federal flood insurance policy in San Marcos, from FEMA’s records: 0.6 per 1,000 homes, fewer than 88% of the 13,809 U.S. towns with a flood insurance record.
- The Pineapple Express - Southern2 claims · $38K
- The California Atmospheric River2 claims · $167K
- The Winter storm1 claim · $2K
San Marcos isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: San Diego County.5 federal disasters brought FEMA money to San Marcos
Disasters that paid out in San Marcos itself (aid to households or repair grants to the City of San Marcos), newest first, with that year’s flood claims.
- 2024Severe Storm and Flooding20 households applied for aid$17K aid approved
- 2020Wildfires33 households applied for aid$3K aid approved
- 2007Wildfires, Flooding, Mud Flows, and Debris Flows66 households applied for aid$43 aid approved$97K to the City of San Marcos for repairs
- 2004Severe Storms, Flooding, Debris Flows, and Mudslides16 households applied for aid$11K aid approved1 flood claim paid that year
- 2003Wildfires, Flooding, Mudflow and Debris Flow Directly Related T5 households applied for aid$15K to the City of San Marcos for repairs
San Diego County has had 30 natural disasters declared by the President since 1953, most often severe storms, then floods. Not counted: the 2005 Hurricane Katrina evacuee emergency, which covered counties that took in evacuees.
Also 18 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in San Diego County, 2002–2018.
Old photos of San Marcos after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the San Marcos archive →San Marcos and its neighbors
San Marcos is 4th of the 7 graded towns here, from least expected damage per building to most. Tap a town to see its hazards.
| Town | Hazard risk | Mostly (buildings) | Flood claims |
|---|---|---|---|
| Vista | C+more damage than 57% | river and rain flooding | 16 |
| Encinitas | C+more damage than 58% | river and rain flooding | 27 |
| Carlsbad | Cmore damage than 66% | river and rain flooding | 14 |
| San Marcos | Cmore damage than 74% | river and rain flooding | 18 |
| Harmony Grove | C−more damage than 79% | river and rain flooding | — |
| Lake San Marcos | C−more damage than 85% | river and rain flooding | — |
| Escondido | Dmore damage than 89% | river and rain flooding | 28 |
| Elfin Forest | — | 592 residents; we grade 1,000+ | |
Hazard risk = FEMA’s expected yearly building damage per dollar of building value, vs. the 21,298 U.S. towns we grade; the map is shaded by fifths of the same scale. Flood claims = paid federal flood insurance claims on record.
Get ready for what San Marcos faces
A short kit for the hazards that drive the building damage here, what to check before you buy, and where neighbors get alerts.
- Turn around at flooded roads: a foot of moving water can carry off a car.
- Flood insurance usually takes 30 days to start, so buy it before the forecast.
- Keep papers and medicines up high, in a grab-and-go bag.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- Clear dead leaves and brush within 5 feet of the house.
- Sign up for local alerts and know two ways out.
- Keep N95 masks for smoky days.
- Look up the address on FEMA’s flood map.
- Ask the seller or landlord whether it has ever flooded, and what flood insurance costs there.
- Get a flood insurance quote early: policies usually start 30 days after you buy.
Know where neighbors sign up for alerts? Add it to the Handbook so everyone has it.
Questions about natural hazards in San Marcos
Is San Marcos at risk for natural disasters?
On FEMA’s National Risk Index, San Marcos has higher expected damage per building than 74% of U.S. towns: C for hazard risk, #130 of 847 in California. Most of the expected damage is river and rain flooding (72%) and earthquakes (18%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does San Marcos flood?
Flood insurance has paid 18 claims in San Marcos since 1978, $356K in all, or 0.6 per 1,000 homes, fewer than 88% of U.S. towns with a flood insurance record. 1 properties have flooded more than once. The most claims came from Pineapple Express - Southern (2).
Is San Marcos in a flood zone?
Flood zones are drawn street by street, so the answer depends on the address: look it up on FEMA’s flood map. In San Diego County, 24% of homes in mapped flood zones carry federal flood insurance, and 0.7% of all homes do.
How much is flood insurance in San Marcos?
FEMA’s Community Rating System list shows no discount for San Marcos’ flood program. Premiums depend on the building; policies usually start 30 days after you buy, so get a quote early.
What was the biggest storm in San Marcos?
By FEMA money that reached San Marcos, Wildfires, Flooding, Mud Flows, and Debris Flows (2007): 66 households applied for aid, $43 approved, and $97K to the City of San Marcos for repairs. By flood claims, Pineapple Express - Southern: 2 paid, $38K.
Is San Marcos at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (72%), and San Marcos’ rate for it is higher than 78% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in San Marcos.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where San Marcos’ residents lived in the 2020 census; OpenFEMA: NFIP redacted claims, multiple-loss properties, community status book and residential penetration rates, housing assistance (owners and renters), public assistance funded projects, hazard mitigation properties and disaster declarations. Homes: Census ACS 2020–24. Preparedness tips: Ready.gov. FEMA’s model is an average of expected damage, not a forecast. How hazard risk is graded.