Port Costa’s biggest natural hazard is earthquakes
Most of the natural-hazard damage FEMA expects in Port Costa comes from earthquakes, and overall the risk is very high for a U.S. community.
What stands out about Port Costa’s weather risks
Read from FEMA’s records below. The page puts what stands out first.
Does Port Costa flood? No paid flood claims on record
FEMA’s records show no paid flood insurance claims in Port Costa. That’s not a promise: most homes don’t carry flood insurance, so small floods go unrecorded.
Port Costa isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Contra Costa County.How exposed is Port Costa?
FEMA expects yearly storm and flood damage to homes and buildings here to be higher than in 90% of U.S. communities, mostly from earthquakes and inland flooding.
Rated higher than 910 of the 1,619 California towns we cover.
Port Costa is smaller than a census tract, so it shares the figures of the tract around its center.
What Port Costa faces
Each hazard’s share of the damage FEMA expects here, and how it compares with the rest of the country.
Earthquakes
Inland flooding
Federal disasters declared here
None of the disasters declared for Contra Costa County shows FEMA aid or repair money reaching Port Costa itself in FEMA’s records.
Contra Costa County has had 17 natural disasters declared since 1953, most often floods and severe storms.
Get ready for what Port Costa actually faces
A short kit for its top hazards, what to check before you buy, and where neighbors get alerts.
- Drop, cover and hold on.
- Strap tall furniture and the water heater to the wall.
- Know how to shut off the gas.
- 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.
- Trim dead limbs over the house and driveway.
- Tie down trash cans and outdoor furniture.
- Stay clear of downed lines and call the utility.
- 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.
Most disasters here begin in December–February
The month each of Contra Costa County’s 17 declared disasters began, since 1953.
What these numbers can and can’t tell you
- An average, not a forecast. FEMA’s National Risk Index estimates the damage 18 kinds of natural hazards cause in a typical year, from decades of records and models. A quiet decade can follow a bad year.
- Compared by rate. “Higher than N%” compares yearly damage as a share of what’s there, so a big city isn’t rated riskier just for having more buildings.
- Money that reached town. Flood claims are matched to Port Costa’s own flood-insurance community; household aid to the registrant’s city; repair grants to Port Costa.
- It follows property value. FEMA’s model weighs damage to buildings, so a place that recently lost many homes can rate lower than it feels.
Storm stories
Memories, warnings and help from neighbors in Port Costa.
Your answer becomes a post in Town Square.
Sources: FEMA National Risk Index (December 2025); 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. Census tracts: U.S. Census Bureau. Preparedness tips: Ready.gov. An average of past damage, not a forecast.