Flood Facts: NYC

What is this: in doing research on flooding in the area, we come across many numbers and stats in many places. So here is running list of items we have found, think are interesting, and help tell the story of flooding in the area. (We cant verify all of these but try to use good sources).

Notes:

  • Some might seem like they need updating, but its the latest we found

  • We haven’t verified all these but tried to find reliable sources

  • What do you see? If you have an update, or a stat you think we should list - or try to get - please let us know in comments below.

Q:What is risk of flooding in New York City?

  • We made the top 10 list!

  • According to a report from Union of Concerned Scientists, which looked at nearly 1,100 assets along the U.S. coastline, they ranked New York as the ninth state with the most critical infrastructure at risk of flooding in 2050.

Q:How many green infrastucture projects has NYC initiated to help with flooding?

  • The city has added over 13,000 green infrastructure assets, like rain gardens and storage tanks, that collect water when flooding occurs to keep sewers from overflowing. Starting in 2026, all city-owned infrastructure and public facilities will be required to meet a stringent set of design criteria to better withstand extreme weather.

Q: How much rain water collects on your property in a 1 inch storm?

  • Multiply your property size x 0.56 to calculate your total water potential per 1 inch of rain

  • Example: an 18x50 foot townhouse can have ~504 gallons of water coming off the roof in 1 inch of rain

  • Greywater Action

  • Related story on Rain Barrels in The City Sponge

Q: How often does it rain more than 1 inch suddenly in NYC?

Q: How much damage can a 1 inch sudden rainstorm cause?

  • Depending on how low your exposure space is, 1 inch of water can cause up to $25,000 in damage, then flood insurance might make sense, especially if you spend more than $500 a year dealing with flood issues.

Q: Does 1 inch of rain contribute to water pollution?

  • Per the GCC: ”Combined Sewer Overflows (CSOs ) are the greatest source of ongoing pollution to the Gowanus Canal. The overloaded sewer system currently discharges about 363 million gallons of raw sewage and polluted run-off, or combined sewer overflow (CSO), into the Gowanus Canal each year, spread over about 40 rainfall events.”

Q: What about sewer backup and how does that relate to flood insurance?

A: Covered, but only if by “flood” vs something else.

  • According to NFIP: “Damage caused by a sewer back up is covered by flood insurance IF the backup is a direct result of flooding.”

  • My insurance broker said it like this: “if it affects multiple properties (2 or more homes) and caused by natural occurrence.” So that is consistent with NFIP.

  • BUT….BUT….IF the sewer backup is NOT caused directly by flooding, the damage is NOT covered under flood insurance. 

Q: Where does “the line” STOP for regular homeowners insurance with regard to flooding?

A: Best to think about homeowners insurance as stopping at the sidewalk level.

  • Regular homeowners /renters insurance will generally NOT cover the items in your basement when flooded. If you have been through a flood before, you know it doesn’t take a lot of water to create a lot of work and cost.

Q: If walls are damaged, is finishing the walls (plaster, painting) covered by flood insurance?

A: Sheetrock, insulation, repair IS covered but NOT taping, sanding, painting.

  • Only replacement (not finishing) and only up to 2 feet above waterline (any higher than that is your cost).

Q: I lived without flood insurance for years, isn’t this just for people in high risk flood zones?

A: Not anymore. That was my POV, but now I’m rethinking it given recent events and what I learned.

  • People outside of high-risk flood areas filed over 40% of all National Flood Insurance Program (NFIP) claims (2014-2018).

  • 1 in 3 flood insurance claims come from LOW and moderate flood risk zones.  Since 1996, flooding has affected 99% of U.S. counties. 

  • Just in NY State in 2023: $52M was paid out by NFIP.  That’s a lot in one year.

Q: What is “Seepage”and why is that the biggest surprise for people when people try to claim damages from flooding?

A: Seepage is water coming from below.

  • My insurance broker said the biggest surprise is that “seepage” is NOT covered.

  • “Seepage” is water coming into the basement through the foundation, the walls, the floor or a little drain on the floor (99% of those are clogged) is seepage is NOT covered in regular homeowners insurance, NOR is it covered by optional flood insurance.

  • The NFIP defines it like this: “Example of EXCLUDED coverage: any damage caused by seepage, or any subsurface water flow or a condition of flow of water beneath the earth’s surface.”

  • So underground streams, rising water tables (which have been rising in recent years due to more rain), or maybe standing water near your place could be coming in through your older foundation walls or floors. This is NOT covered by flood insurance.  [ Note: we hope to cover underground water sources in another newsletter. ]

Q: Does Flood insurance reimburse me for preventative steps I take to prevent flooding?

A: Yes, up to $1,000 according to the FEMA / NFIP “Flood Loss Avoidance Policy.” 

  • I called FEMA to verify this and they said: “Yes it is a ‘thing’…IF you have a policy already in place.”   Here are the reimbursable expenses:

    • Sandbags (including the sand to fill them) 

    • Dirt to create temporary levees

    • Water pumps

    • Plastic sheeting and lumber used in connection with any of these items listed above

    • Labor – you may claim labor, including your own or a family member’s labor, at the federal minimum wage. Labor charged by a professional may also be reimbursed. 

  • Tips: Keep receipts.  Take photos before, during, after.  Submit to the insurance agent like a regular claim. 

  • Policy is here: https://www.floodsmart.gov/flood-risk and see pic below. 

Q: I can see how this would cost me money, but how would it save or make me money?

A: It does cost some now…but saves more. You also increase safety, reduce legal risk and getting dinged on price reduction. Lastly, flood insurance reimburses for some mitigation work.

  • Some stats: In 2021 in New York State, 7,645 homes were purchased that were estimated to have been previously flooded according to an NRDC report.

  • It goes on to say: “the average home in New York State with prior flood damage has an expected average annual loss of $3,126, compared to $93 for the average home.

  • Over the course of a 15-year mortgage, average expected damages to the previously flooded home equate to $46,887 (in today’s dollars); for a 30-year mortgage flood damages equate to $93,774.”

Q: How many people in Brooklyn get flood insurance?

About 20% according to an insurance broker agent we spoke to

Q: How much water does the NYC subway pump out everyday?

  • 14-17m gallons DAILY according to the MTA at recent Cornell Urban Tech Summit 2024.

Q: How much progress has NYC made since Hurricane Sandy on key goals for flood mitigation?

Some. But not in all areas. Example: Of 1,500 catch basins needing replacement, 48 have been done Stats here from NYC Comptroller’s Office on items such as number of people enrolled in Notify NYC alerts, catch basin maintenance and number of special trucks to clear out catch basins to improve sewer flow, funds spent on NYC resiliency:

Q: What is the deal with these terms: “100 / 500 year floodplain”?

A: Big topic…but the short answer is that is how they describe the probability of being flooded.

  • 100 year: 1% chance of being inundated by a flood each year

  • 500 year: 0.2% chance of being inundated by a flood each year 

  • But as people in NYC can attest, floods are happening more often than that, so it really it is just an indicator of more or less flooding potential. 

Q: How many people in NYC have DROWNED in basement apartments in recent years?