Learn About Norwalk's Flood Zone

What is a Flood Zone?

Flood Zones are geographic areas that FEMA has defined according to varying levels of calculated flood risk.  Any area in Norwalk can experience flooding, but flood hazard zones have a higher risk of flooding and are subject to special regulations and flood insurance requirements. 

Norwalk has areas that FEMA has identified as being at higher risk for both riverine and coastal flooding.  While both types of flooding can result in water damage to properties, the amount and type of damage can vary based on your property's location.  Flood mitigation measures can also vary based on the type of flooding expected in an area.  

FEMA maps the flood zones in communities across the US - including Norwalk - and identifies areas of varying flood risk on Flood Insurance Rate Maps (FIRMs). FEMA creates FIRMs to inform flood insurance pricing in the National Flood Insurance Program (NFIP) and to guide floodplain management/flood hazard zone regulations for communities.  

FEMA has developed a 'story map' that explains flood concepts and explains the FEMA FIRM maps.   This webpage is focused on Coastal Floodplain Mapping, but is loaded with useful information for all. coastal floodplain pic Opens in new window

Is my property within a Flood Hazard Zone?

Below are links to two external websites that are searchable by street address.  Keep in mind, neither of these two sources of information can predict whether flooding will occur at a property, but they can both be used as tools to assist you in assessing risk. 
floodmap FIRMflood factor logo cube
View the official FEMA FIRM for any property by entering an address in FEMA's map viewer.To learn more about the flood risk for your property, try using the information from Flood Factor.

What should I do if my property is within the flood zone?

If your property is located within a Special Flood Hazard zone, you will need to look more closely at the FEMA FIRM map to determine which flood hazard zone your property is within and if there is base flood elevation (BFE) information in the vicinity of the property.   The BFE is the elevation of surface water that is predicted to result from a flood that has a 1% chance of equaling - or exceeding - that level in any given year.

Depending on your proposed construction and the flood zone your property is within, there will likely be some additional structural requirements, certification documentation, and budget considerations for building in a flood hazard zone. 

The Building Department can inform you of any Building Code requirements for construction within a flood zone. Article 110 of the Zoning Regulations describes the flood zones and related requirements for work within any Flood Hazard Zone within Norwalk.  Refer to the official language in the regulations here.  

Some of the requirements to consider prior to initiating work within a Flood Hazard Zone: 

Structural Requirements

  • Flood vents or break-away walls
  • Finished living space must be constructed at elevations at least one foot above BFE
  • Flood-resistant materials

Documentation Requirements 

  • Proposed flood certification by a licensed professional engineer or architect
  • Final (post-construction) flood certification by licensed professional engineer or architect 
  • Final FEMA elevation certificate (issued by a CT licensed Land Surveyor) when bringing a dwelling into full flood compliance

Substantial Improvement/FEMA Budget (the 50% Rule)

Rebuilding after a storm, adding on, renovating or remodeling your home or business? 

Structures in a flood zone that are not flood compliant are subject to FEMA limitations on substantial improvement.  

Substantial Improvement:  Any repair, reconstruction, rehabilitation, addition, or other improvement of a structure where the cumulative cost of improvement exceeds 50% of the market value of the existing structure prior to any work.

The City of Norwalk cumulatively tracks the substantial improvement costs back to 1978 when the flood regulations were first adopted. The allowed amount is restricted to 50% of the appraised value (at the time of the first improvement) of the structure.  If cost tracking indicates a home is at or above the 50% threshold, then the home would need to be made flood compliant before any more improvements are permitted. 

The City's goal is to reduce flood damage risks and  reduce costs of flood damage over time. 

  • The FEMA budget is taken into account when the first alteration of any wall, ceiling, floor or other structural part of the building commences, whether or not that alteration affects the external dimensions of the structure.  
  • All improvements are tracked; whether or not a Zoning Permit is required.  These include, but are not limited to, projects such as replacement windows, siding, and roofing. 
  • The budget is cumulative from the first instance of work (post 4/24/78) until the budget has been reached or exceeded.  Once reached or exceeded, the home must then be made flood compliant. FEMA cover of SI-SD Opens in new windowFEMA provides additional information regarding Substantial Improvement in the Bulletin. Please note Norwalk has adopted a higher standard for cost tracking as referenced in the Bulletin
  • Refer to the Zoning Regulations for possible exclusions of cost tracking for work that is required for local health or safety specifications and for certain historic structures. 

What if I want or need to do work in excess of my FEMA Budget?

Several solutions can achieve compliance. The solution selected for any given structure will depend on several factors, such as flood zone (Zone A or V), the type of foundation, feasibility, and whether the structure is residential or non-residential.

  • Some solutions include:
    • Elevate or raise structure one foot above the BFE (attendant mechanicals must also be raised);
    • Fill basement;
    • Wet floodproofing (installing flood vents in below-grade enclosures); and  
    • Dry floodproofing in commercial structures only (self-stabilizing flood barriers).

Everyone lives in an area with some flood risk—it’s a question of whether you are in a high-risk, low-risk, or moderate-risk flood area.