Photo: Stephen R. Gold · Public domainFEMA expects more hazard damage per building in Penngrove than almost anywhere in the U.S., mostly from river and rain flooding
On FEMA’s National Risk Index, Penngrove gets a D− for hazard risk: among the highest expected damage per building of U.S. towns. Most of that expected damage is river and rain flooding (60%), then earthquakes (31%). Flood insurance has paid 1 claim here since 2021.
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 Penngrove 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 Penngrove’s grade
River and rain flooding is 60% of the building damage FEMA expects in Penngrove, and Penngrove’s rate of river and rain flooding damage is in the top 2% of U.S. census tracts. Earthquakes add 31%, at a rate in the top 4% of U.S. census tracts.
D− among the highest expected damage per building of U.S. towns (21,298).
Penngrove’s residents live in 3 census tracts; FEMA’s figures are combined by where they live.
In dollars, FEMA expects about $5.2M a year in losses across Penngrove: $4.7M to buildings, the rest to people and crops.
Does Penngrove flood? Rarely: 1 flood claim since 2021
Every paid claim on a federal flood insurance policy in Penngrove, from FEMA’s records: 1.0 per 1,000 homes, fewer than 79% of the 13,809 U.S. towns with a flood insurance record.
Penngrove isn’t in FEMA’s Community Rating System, which cuts flood insurance up to 45% in towns that do extra flood-proofing.
Insurance rates: Sonoma County.2 federal disasters brought FEMA money to Penngrove
Disasters that paid out in Penngrove itself (aid to households or repair grants to Penngrove), newest first, with that year’s flood claims.
- 2017Wildfires30 households applied for aid$500 aid approved
- 2005Severe Storms, Flooding, Mudslides, and Landslides8 households applied for aid$17K aid approved
Sonoma County has had 24 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 8 FEMA wildfire suppression grants (Fire Management Assistance, not a disaster declaration) for fires in Sonoma County, 2004–2020.
Old photos of Penngrove after a storm or flood belong in the town’s history. Add one, or share what you remember below.
Add to the Penngrove archive →Get ready for what Penngrove 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 Penngrove
Is Penngrove at risk for natural disasters?
On FEMA’s National Risk Index, Penngrove has among the highest expected damage per building of U.S. towns: D− for hazard risk. Most of the expected damage is river and rain flooding (60%) and earthquakes (31%). This is FEMA’s model of an average year for today’s buildings, not a forecast.
Does Penngrove flood?
Flood insurance has paid 1 claim in Penngrove since 2021, $82K in all, or 1.0 per 1,000 homes, fewer than 79% of U.S. towns with a flood insurance record.
Is Penngrove 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 Sonoma County, 31% of homes in mapped flood zones carry federal flood insurance, and 1.1% of all homes do.
How much is flood insurance in Penngrove?
FEMA’s Community Rating System list shows no discount for Penngrove’s 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 Penngrove?
By FEMA money that reached Penngrove, Severe Storms, Flooding, Mudslides, and Landslides (2005): 8 households applied for aid, $17K approved.
Is Penngrove at risk from river and rain flooding?
It is the largest share of the building damage FEMA expects here (60%), and Penngrove’s rate for it is in the top 2% of U.S. census tracts.
Storm stories
Memories, warnings and help from neighbors in Penngrove.
Sources: FEMA National Risk Index v1.20 (December 2025), census-tract table, combined by where Penngrove’s 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.