If you own property on Long Island, flood zones matter. They determine whether you need flood insurance, how much that insurance costs, what you can build, and in some cases, whether you can get a mortgage at all.
Many property owners assume flood zone designations are permanent. They’re not. FEMA updates flood maps periodically, and properties that weren’t in a flood zone can suddenly be designated as high-risk. Properties that were considered high-risk can sometimes be reclassified to lower-risk zones.
These changes affect thousands of Long Island homeowners, and while most of the time we don’t think about it, there are going to be situations where you need to know your flood zone before you make a decision on your property. If you need a survey to help you with your decision-making needs on Long Island, reach out to Aerial Land Surveying today.
How FEMA Flood Zones Work
FEMA creates Flood Insurance Rate Maps, or FIRMs, that divide areas into different flood zones based on flood risk. The zones determine flood insurance requirements and rates.
The main flood zones you’ll encounter on Long Island include:
- Zone AE – High-risk flood area with a 1% annual chance of flooding (the “100-year floodplain”). Properties in this zone typically require flood insurance if you have a federally backed mortgage. Base flood elevations are provided.
- Zone VE – High-risk coastal flood area with wave action. These are the highest-risk zones, usually right along the coast. Insurance is more expensive here than in Zone AE.
- Zone X (Shaded) – Moderate flood risk with a 0.2% annual chance of flooding (the “500-year floodplain”). Flood insurance isn’t required but is recommended.
- Zone X (Unshaded) – Minimal flood risk. Flood insurance typically isn’t required or recommended, though flooding can still occur.
Your flood zone determines your flood insurance requirements and costs. But these designations change over time as FEMA updates its maps based on new data.
Why Flood Zones Change
FEMA doesn’t typically update flood maps arbitrarily. Changes happen for specific, measurable reasons based on new information about flood risk in an area. For example:
- Better Data – Better data and improved modeling technology are major drivers. Older flood maps were created with limited data and less sophisticated modeling. As FEMA updates maps, they use better elevation data, more detailed storm surge modeling, and improved understanding of how water moves through developed areas. This can shift boundaries between flood zones.
- Development – Development changes flood patterns. When new construction happens – subdivisions, commercial buildings, parking lots – it changes how water flows across the land. More impervious surfaces mean more runoff. Drainage systems get overwhelmed. Areas that didn’t flood before start flooding. FEMA updates maps to reflect these changes.
- Natural Changes to Land – Natural changes also affect flood risk. Coastal erosion moves the shoreline inland. Dunes that provided protection get washed away in storms. Wetlands that absorbed water get filled or degraded. These changes increase flood risk for properties that were previously protected.
- Climate Change – Climate and sea level rise play a role too. Sea levels around Long Island have risen measurably over the past several decades. Higher baseline water levels mean storm surges reach farther inland. FEMA updates maps to account for current conditions, not conditions from 30 years ago when the old maps were created.
- Natural Disasters – Major storms trigger map updates. After significant flooding events like Hurricane Sandy, FEMA reassesses flood risk in affected areas and often remaps entire regions. Properties that experienced flooding during major storms are more likely to be reclassified into higher-risk zones.
Reclassification may also occur as a response to changes at higher levels of government, as those in charge may choose different measurements over time. What FEMA considered a flood risk in the past may or may not be considered a flood risk now.
What Happens When Your Property Gets Remapped?
When FEMA updates flood maps in your area, you receive notification if your property’s flood zone designation changes. The notification explains the proposed changes and provides a period for public comment before the new maps become official.
If your property moves into a higher-risk flood zone, several things happen:
- Flood Insurance Requirements – If you have a federally backed mortgage and your property is remapped into Zone AE or VE, you’ll be required to purchase flood insurance. Lenders typically won’t close on a property in a high-risk flood zone without proof of flood insurance.
- Insurance Costs – Flood insurance in high-risk zones is significantly more expensive than in moderate or low-risk zones. Annual premiums can range from a few hundred dollars to several thousand depending on your property’s elevation relative to the base flood elevation.
- Property Value Impact – Being mapped into a flood zone can affect property values. Some buyers avoid flood zone properties due to insurance costs and flood risk. Others factor the insurance cost into their offer price.
- Building Restrictions – Properties in flood zones face stricter building requirements. New construction or substantial improvements typically need to meet specific elevation requirements. Finished living space below the base flood elevation may not be permitted.
The good news is that flood zone designations aren’t always correct. If your property gets remapped into a flood zone but you believe the designation is wrong, you have options.
How Elevation Surveys Can Change Your Flood Zone Status
Just because FEMA’s map says your property is in a flood zone doesn’t mean it actually is – or at least doesn’t mean it needs to be treated that way for insurance purposes.
FEMA’s flood maps show broad areas, but they don’t account for specific elevation differences between individual properties. Your home might sit higher than surrounding properties. Your lot might have been graded to raise the elevation. Your finished floor might be above the base flood elevation even though the map shows your property in a flood zone.
An elevation survey measures your property’s actual elevation and compares it to FEMA’s base flood elevation. If your lowest finished floor is above the base flood elevation, you may qualify for lower insurance rates even if your property is technically in a flood zone.
A FEMA Elevation Certificate is the official document that records these measurements. Insurance companies use Elevation Certificates to determine accurate flood insurance rates. In many cases, having an Elevation Certificate reduces insurance costs significantly – sometimes by thousands of dollars per year.
Elevation Certificates are also required for new construction or substantial improvements in flood zones. You need one to get a building permit and to prove compliance with local floodplain management regulations.
Challenging a Flood Zone Designation
If you believe FEMA’s flood map is wrong for your property, you can challenge the designation through a process called a Letter of Map Amendment (LOMA) or Letter of Map Revision (LOMR).
A LOMA is used when your property was incorrectly included in a flood zone. This typically happens when improved elevation data shows your property is actually at a higher elevation than FEMA’s maps indicate. If approved, a LOMA officially removes your property from the high-risk flood zone.
A LOMR is used when physical changes to your property or the surrounding area have changed flood risk. This might include fill that raised your property’s elevation, new drainage systems, or other improvements that reduce flood risk.
Both processes require detailed surveying and documentation. You might need to provide:
- Accurate Elevation Data – Topographic surveys and elevation certificates that show your property’s current elevation relative to the base flood elevation.
- Property Boundary Information – Boundary surveys that clearly define your property lines and show where improvements are located.
- Supporting Documentation – Engineering reports, grading plans, drainage studies, or other technical documents that support your case.
FEMA reviews the application and makes a determination. If approved, your property is officially remapped, which affects insurance requirements and rates going forward.
Why Long Island Properties Face Unique Flood Challenges
Long Island’s geography creates specific flood risks that affect how FEMA maps the area.
- Coastal location means significant portions of Long Island face storm surge risk. Properties near the water are especially vulnerable to flooding during hurricanes and nor’easters.
- Low elevation across much of the island means even properties not directly on the water can be in flood zones. Water doesn’t drain away quickly on flat terrain.
- Dense development changes natural drainage patterns. When wetlands and open space get developed, water that used to be absorbed by vegetation now runs off into streets and yards.
Aging infrastructure in many areas means drainage systems designed decades ago can’t handle current conditions. Undersized pipes and deteriorating stormwater management create flooding that didn’t exist when the systems were new.
These factors combine to make flood zone mapping complicated on Long Island. FEMA’s maps reflect these realities, which is why so many properties end up in flood zones – and why those zones change as conditions change.
Getting Accurate Survey Data
Whether you’re dealing with a flood zone remapping, applying for a LOMA, or just want to understand your property’s flood risk, accurate survey data is essential.
Aerial Land Surveying provides elevation surveys, FEMA Elevation Certificates, topographic surveys, and other surveying services throughout Long Island and downstate New York. We use both ground-based and aerial technology to provide accurate measurements that meet FEMA requirements and local regulations.
If your property has been remapped into a flood zone, or if you’re buying property in a flood zone and want to understand your options, contact Aerial Land Surveying at (833) 787-8393. Accurate elevation data can save you thousands of dollars in unnecessary flood insurance costs and help you make informed decisions about your property.