How to Easily Calculate Sea Level Rise For Your Own Home

Sea level rise is not on the radar for many people.  But in terms of our financial security, it could become one of the most important things to calculate sea level rise when buying a home or planning for the future.

That may sound dramatic, but the oceans are rising at an increasingly faster rate. According to some studies, the impact of rising seas on our homes affects over 600 million people worldwide. Forty percent of the population here in the lives near a coastal area

A picture of a small home surrounded by flooding.

In this article, we focus on understanding sea level rise, factors to consider when finding or planning where you’ll live, and long-term effects on your home value and overall future wealth.

If you want to jump directly to our calculator – click here.

What is Sea Level Rise Anyway?

The short version is that the earth is heating up, mainly due to human activity and global warming. This creates an expansion of the ocean’s water.

According to NASA’s Global Climate Change website:

“Sea level rise is caused primarily by two factors related to global warming: the added water from melting ice sheets and glaciers and the expansion of seawater as it warms.”

Nature Doesn’t Care What We Think.

While this issue has been heavily politicized, especially in the United States, it doesn’t matter what you or I think. Facts are facts, and I would argue that if you’re looking at living in or buying a home anywhere near the coastline, you’ll want to take a few minutes at least to see how rising seas may affect your home over the years.

Because like it or not, nature doesn’t care about what we believe.

Courtesy of Climate.gov – Contributors to Global Sea Level Rise 1993-2018

Florida: A Case Study in Sea Level Rise

Florida has a population of over 21 million people and thousands of people moving here daily.  That makes for a good example of what’s going on in real time regarding sea level rise and real estate.

Many people (myself included) enjoy living here for the beaches, low taxes, sunshine, and great weather year-round. But the effects of sea level rise persist daily.

Sporting over 8,000 miles of shoreline, Florida is especially at risk from rising water levels. A study from Climate Central estimates that 65,000 homes in Florida (worth over $35 billion) are expected to be underwater or impacted daily by high tides in 2040.

Much of Florida’s land is at or just a few feet above sea level. Much of this land, particularly in the south Florida region, is low-lying and made of porous limestone underneath the surface. This means that as sea water rises, it creeps inland and underneath existing homes. It infiltrates freshwater supplies and effectively rises from underneath you instead of just from the coastlines, among other things.

Miami

This city has been in the spotlight over the past few years, serving as the “canary in the coal mine,” so to speak. The city passed a $400M general obligation bond paid for by local residents to fight back rising oceans. According to the Southeast Florida Climate Compact:

“Nearly half of the bond proceeds will be directed toward reducing flooding risks and sea level rise mitigation, with another quarter invested in improving affordable housing. The remaining will be split among enhancing public safety and improving parks, cultural facilities, streets, and infrastructure.”

Courtesy of NOA: Change in sea level since 1880

Sunny Day Flooding

In addition to hurricane activity and tidal surge, the term “sunny day floods” has now become a thing.  In some cases, sea level rise has created flooding for 40 straight days

There are tons of great resources and documentaries online for more info, but you get the idea. This is an example of what’s happening right now in many cities and towns around the world.

Courtesy of Climate.gov – Projecting the different scenarios for levels of sea level rise.

The Effects of Rising Seas On Your Home: Factors to Consider

Bringing this back to how it affects you and your home, here are some very real and specific consequences of how sea level rise can hit home (pun intended).

Overflowing Sewage

Many cities have decaying or leaky pipes directly below the surface. When the seas rise enough to submerge the sewage system, naturally, there’s nowhere to go. You can use your imagination (hopefully, you’re not eating), but cities like Fort Lauderdale are already dealing with spills into rivers and canals and pipes backing up, among other things.

Contamination of Fresh Water Supply

As time goes on and oceans continue to rise, there is an increased risk of salt contaminating freshwater aquifers and wells.

Courtesy of the National Environmental Education Foundation

Flooding and Flood Insurance

Beyond the water itself infiltrating your property and causing costly damage, flood insurance premiums are only getting more expensive. If you’re in an official flood zone, lenders will require flood insurance on the property.

Depending on the price, this required insurance can add hundreds to the monthly costs of owning a home. Other knock-on effects include slowing your personal wealth-building due to increased costs and suppressing home value over time as well.

The Numbers Don’t Work

There’s a real systemic issue arising from increased floods and sea level rise, in addition to the above problems. Private insurance companies, in some cases, are entirely pulling out of cities and states. Those states are left with only the federally funded FEMA National Flood Insurance Program, which is financially underwater, itself.

Courtesy of FEMA – Graph of the National Flood Insurance Program Debt

FEMA has a great tool where you can look up your exact flood zone by address here. The map will show different shades of flood map risk, and you can see whether or not you’ll need flood insurance.  Here’s an example:

Clear and orange (at risk) shaded areas: no insurance needed. Blue shaded area (needed) if you have a loan on the property.

Resale Value

As time goes on and seas only get higher, homes near or at sea level will go down in value. Usability, insurability and mortgage default risk will all play into this.  A home that faces continued flooding, unusable roads nearby, or prohibitively high insurance premiums will not be in demand. There are places around the country where this is already happening.

Ability to Get a Mortgage or Refinance

You may not have an issue getting a loan right now. But if you plan to keep the home a long time, you may run into big problems in the future.

This is speculation, but let’s say that in fifteen years you want to refinance or get a new loan. The house may now be considered high risk, and you may be unable to get another 30-year loan on it.

Or you may not be able to get it insured due to the water levels rising. That will also prevent you from taking a loan on the property. It’s also possible that you could get put into a much higher interest rate bracket, since all the above scenarios put you at a higher risk of defaulting on your loan.

“Not only are the mortgage loans on these homes at growing risk of default if the value of the properties drops, but each successful sale of one of these homes represents the potential transfer of a major latent financial liability,” noted the authors of the Union of Concerned Scientists report. “Eventually, the final unlucky homeowners will hold deeds to significantly devalued properties.”

NPR

Personal Finance and Wealth-Building

We all work so hard to pay the bills and maybe save a little bit beyond that. It’s widely accepted that over time, real estate can be one of the best wealth-generating tools you’ll use in your lifetime. And even if a particular home isn’t at risk in this moment, it may be in 10-20 years from now. These issues may not be visible right now. But there are potentially some significant problems lurking under the surface (OK, enough puns).

At the end of the day, someone is going to have to pay for all of this. And you can bet that insurance and mortgage companies will not be the ones wanting to do it. There are different factors with every home, but you can imagine how sea level rise could affect things.

How to Calculate Sea Level Rise On Your Own Home

Whether you’re already in a home or looking to buy soon, it’s a good idea to know how the property could be affected in the future. Some may have no issues because they are well above any flooding or coastlines. If so, awesome!

But if you’re anywhere near water, spending a few minutes on it could give you some peace of mind.

The good news is that most of the work has been done already by some amazing scientists and organizations. Our calculator takes things further by:

1) Incorporating tools to find the elevation on your own address

2) Estimating the average daily sea level rise

3) Running scenarios going out 100 years

4) Including calculations for inches, feet, and meters

5) Creating a table that shows you the potential new net elevation after sea levels rise through the years.

A picture of our 100-year table showing how to calculate sea level rise for your own address.
Example of inputting your own current elevation to estimate possible sea level rise over the next 100 years.

To get a copy for yourself, you can download it here for free. It’s an easy link to a Google Sheet, which requires no additional software or space on your computer –

Download our Sea Level Rise Calculator Here:

Your home may or may not be directly threatened by sea level rise. But we hope you’ve seen how rising sea levels affect all of us who live anywhere near a coastal region.

It’s on us to plan for the future, instead of ignoring it until the water is on our doorstep. Together, we can adjust to the inevitable environmental changes in the most affordable and comfortable way for everyone.

Erin Shine

Erin Shine

Founder | Attainable Home

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